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The purpose of our study is to determine the influence of elastic energy on the spinodal decomposition ranges of InAlGaN alloys lattice-matched to GaN. The distinction in lattice constants of the binary compounds constituting these alloys gives rise to their deformation energies. Such energies provide the tendency to disintegration that can lead to an appearance of the thermodynamically unstable states with respect to the decomposition. The initial stage of spinodal decomposition of the InAlGaN quaternary alloys is accompanied by transfers of atoms over distances of a lattice parameter. Accordingly, these transfers produce a thin two-layer region with negligibly small differences in their compositions. Formation of these layers causes the elastic energy. The alloys are represented as quaternary regular solutions. The internal deformation energy is calculated with the interaction parameters estimated by the valence force field model. The spinodal decomposition ranges of these materials are demonstrated up to 580 °C (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The Raman frequency shifts and the depolarization ratio of the Raman lines have been determined for the compounds NaCl. AlCl3 and NOCl. AlCl3 (in the last case with qualitative polarization measurements only). The preparation of pure NOCl. AlCl3 is described in extenso. The properties of the compound finally obtained are different from those given in the literature. NaCl. AlCl3, has to be considered as Na+AlCl4−, and NOCl. AlCl3 as NO+AlCl4−. There is a perceptible interaction between nitrosyl and the chlorines of AlCl4− in the last compound. The properties of NOCl. AlCl3 are intermediate between those for a pure heteropolar compound (NO+AlCl4−) and a pure molecular compound NOCl. AlCl3, being more alike those of the heteropolar form. Force constants have been calculated for AlCl4;−, making use of the Lechner formulae and of those for a Urey-Bradley field and also of those for the orbital valence force field of Heath and Linnett.

A set of force constants for dimethyl sulfide and deuterated analogues CH3SCD3 and (CD3)2S has been calculated using a modified general valence force field. The calculated force constants reproduce the fundamental frequencies observed fairly well.

Powell c.s. deduced from an X-ray study that solid PCl5 has to be considered as [PCl4+] [PCl6−]. From the distances between P and Cl in PCl4+ and in PCl6− given by the authors, force constants fPCl4+ and fPCl6− have been calculated using Badger's rule. From these f values and by a comparison with the results of a similar calculation for SiCl4 it follows that the strongest lines of the Raman spectrum of PCl5, namely 358(15) and 451 (7), belong to v1(PCl6−) and v1(PCl4+) respectively. With these frequencies known, it is possible to make an estimate of the frequencies to be expected for the other Raman-active vibrations of both ions. A probable assignment of Raman shifts to vibrations of PCl4+ and PCl6− is given. Force constants have been calculated for both ions, using formulae based on Nath's force field and on the orbital valence force field introduced by Heath and Linnett, Probable frequency values: PCl4+ 173, 244, 451, 627; PCl6− 244, 285, 358.

The infrared and Raman spectra of CH3HNCOCOOCH3, and the nitrogen-deuterated derivative have been recorded; the fundamentals have been assigned and a valence force field has been calculated.

The potential energy constants of HNSO, DNSO and H 15NSO have been evaluated using Cyvin's W-matrix method employing the General Valence Force Field. Making use of these constants, the mean-square amplitudes of vibration, the Coriolis coupling constants and centrifugal distortion constants have also been evaluated and presented here.

In order to compute later all the force constants and mean-square amplitudes of the generalized valence force field, we are proposing a method for the determination of the U-matrix for XYn groups, and the U-, G-, F- and Σ matrices (Wilson's Method) for XY6, (D3h ) molecules.

The calculation of an approximate Simple symmetry Valence Force Field including determination of diagonal symmetry valence force constants is achieved by using an iterative process derived from the Stepwise Coupling Method (SCM) in the form of the Matrix Polynomial Expansion Method (M.P.E.M.) of Alix. The discussion on the method itself and the comparison with similar methods such as the Eigen-Vector Method (EVM) is given in detail. Numerical examples are given to illustrate the effectiveness of the method.

The infrared and Raman spectra of (CH3)2NCOCOOCH3 and KOOC COOCH3 have been recorded, the fundamentals have been assigned, and a valence force field has been calculated.

All the general quadratic valence force field potential constants of CaMoCl4O2 and K2PtCl4Br2 molecules are evaluated using kinetic constants which in turn is used to obtain other molecular constants. Furthermore, some of the unassigned frequencies are predicted in the present work.

Polyaniline is unique among conducting polymers in that its electrical properties can be reversibly controlled both by the oxidation state of the main chain and by protonation. In the present communication we report normal modes and their dispersion in polyaniline pernigraniline base (PANI PNB) form using Urey - Bradely force field which in addition to valence force field accounts for the non-bonded interactions in the gem and cis configurations and tension terms. Some of the distinguished features of the dispersion curves such as cross-over and Von Hove type of singularities are discussed and possible explanations are given in terms of symmetry considerations. Several new assignments, which are missing in earlier work, are reported.

Eine qualitative Zuordnung der Spektren dient als Ausgangslosung zur Charakterisierung der Schwingungen von (CH3)2SO2 (1), (CH3)2SO(NH) (2 a) und (CH3)2S(NH)2 (3 a) sowie der C- und N-deuterierten Derivate von 2 a und 3 a auf der Grundlage eines Kopplungsstufenverfahrens. Unter Verwendung eines allgemeinen Valenzkraftfeldes erfolgt eine Normalkoordinatenanalyse in Symmetriekraftkonstanten mit einer anschliesenden Berechnung der Energieverteilung der Normalschwingungen bezuglich der Symmetriekoordinaten. Normal Coordinate Analysis of (CH3)2SO2, (CH3)2SO(NH), and (CH3)2S(NH)2 using the Method of Stepwise Coupling The qualitative assignment of the vibrational spectra of (CH3)2SO2 (1), (CH3)2SO(NH) (2 a), and (CH3)2S(NH)2 (3 a) and of the C and N deuterated derivatives of 2 a and 3 a is used in a normal coordinate analysis by the method of stepwise coupling. The force constants and the energy distributions are calculated in symmetry coordinates using a generalized valence force field.

Bei der Umsetzung von [(Mo6Br)Bra6]2− mit AgNO3 Aceton und anschliesender Zugabe von KCN bzw. KNCS entstehen das Hexacyano- bzw, das Hexaisothiocyanatoderivat [(Mo6Br)Y]2−, Ya CN, NCS. Rontgenstrukturanalysen sind an Einkristallen von (Ph4P)2[(Mo6Br)(CN)a6 · 4H2O (1) (triklin, Raumgruppe P1, a = 11,63(3), b = 11,85(1), c = 14,23(5) A, s= 71,8(1)°, β = 67,6(3)°, γ = 62,8(1)°, Z = 1) und (n-Bu4N)2][(Mo6Br)(NCS) a6] · 2Et2O (2) (monoklin, Raumgruppe P21/n, a =11,483(3), b = 16,348(5), c = 20,059(6) A, β = 95,44(3)°, Z = 2) durchgefuhrt worden. In (1) liegen die uber C gebundenen Cyanoliganden als faciale Gruppen mit MoCN-Winkeln von 168,0–171,5° und 174,1–175,7° vor. In (2) bilden die uber N koordinierten Isothiocyanatogruppen in den beiden apikalen Positionen MoNC-Winkeln von 164,4°, die aquatorialen Winkel von 172,7–173,5°. Unter Verwendung der rontgenographisch ermittelten Molekulparameter werden die bei 10 K registrierten IR- und Raman-Spektren der (n Bu4N)-Clustersalze durch Normalkoordinatenanalysen auf der Basis eines modifizierten Valenzkraftfeldes zugeordnet. Die Valenzkraftkonstanten betragen fur fd(MoMo) = 1,41 (CNa) bzw. 1,43 (NCSa), fd(MoBri) = 0,97 (CNa) bzw. 0,96 (NCSa), fd(MoC) = 1,62 und fd(MoN) = 2,09 mdyn/A. Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of [(Mo6Br)Y]2−; Ya CN, NCS By treatment of [(Mo6Br)Bra6]2− with AgNO3 in acetone and addition of KCN or KNCS the hexacyano and hexaisothiocyanato derivates [(Mo6Br)Y]2−, Ya CN, NCS are formed. X-ray structure determinations of (Ph4P)2 [(Mo6Br)(CN)a6]·4H2 O (1) (triclinic, spacegroup P1, a = 11.63(3), b = 11.85(1), c = 14.23(5) A, α = 71.8(1)°, β = 67.6(3)°, γ = 62.8(1)°, Z= 1) and (n-Bu4N)2[(Mo6Br i8)(NCS)a6] · 2Et2O (2) (monoclinic, spacegroup P21/n, a = 11.483(3), b = 16.348(5), c = 20.059(6) A, β= 95.44(3)°, Z = 2) have been performed. The via C coordinated cyano ligands of (1) reveal facial groups with (MoCN) angles of 168.0–171,5° and 174.1°–175.7°. In (2) the via N coordinated isothiocyanato groups at the apical positions show MoNC-angles of 164.4°, the equatorial angles are 172.7–173.5°. Using the molecular parameters of the X-ray determinations the 10 K IR and Raman spectra of the (n-Bu4N) cluster salts are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are fd(MoMo) = 1.41 (CNa), 1.43 (NCSa), fd (MoBri) = 0.97 (CNa), 0.96 (NCSa), fd(MoC) = 1.62, fd(Mo-N) = 2.09 mdyne/A.

Bei der Umsetzung von [(Mo6X)Y]2−; Xi, Ya = Cl, Br; mit AgNO3 in Ethanol/Dichlormethan und anschliesender Zugabe von NaN3 entstehen Octa-μ3-halogeno-hexazido-octahedro-hexamolybdat(2−)-Anionen [(Mo6X)(N3)]2− Rontgenstrukturanalysen sind an Einkristallen von (n-Bu4N)2[(Mo6Cl)(N3)] (1) (monoklin, Raumgruppe P 21/n, a = 14,592(5) A, b = 12,314(5) A, c = 17,039(5) A, β = 101,183(5)°, Z = 2), (n-Bu4N)2[(Mo6Br)(N3)] (2) (monoklin, Raumgruppe P 21/n, a = 14,595(6) A, b = 12,416(5) A, c = 16,960(3) A, β = 100,74(3)°, Z = 2) und (Ph3PNPPh3)2[(Mo6Br)(N3)] (3) (triklin, Raumgruppe P 1, a = 11,092(4) A, b = 13,161(8) A, c = 14,341(11) A, α = 78,085(6)°, β = 82,821(5)°, γ = 84,379(4)°, Z = 1) durchgefuhrt worden. Wahrend die Clusteranionen in den (n-Bu4N)-Salzen eine regelmasige Geometrie aufweisen, verursacht das Kation in der (Ph3PNPPh3)-Verbindung starke Verzerrungen des Clusterkerns mit einer Variation der Bindungslangen Mo-Mo bzw. Mo-Bri um bis zu 8%. Unter Verwendung der rontgenographisch ermittelten Molekulparameter werden die bei 10 K registrierten IR- und Raman-Spektren der (n-Bu4N)-Clustersalze durch Normalkoordinatenanalysen auf der Basis eines modifizierten Valenzkraftfeldes zugeordnet. Die Valenzkraftkonstanten betragen fur fd(Mo-Mo) = 1,53 (Cli) bzw. 1,46 (Bri), fd(Mo-Cli) = 1,09, fd(MoBri) = 0,96, fd(MoN1) = 2,09 (Cli) bzw. 2,36 (Bri) mdyne/A. Synthesis, Crystal Structure, and Spectroscopic Properties of the Cluster Anions [(Mo6X)(N3)]2−; Xi = Cl, Br By treatment of [(Mo6X)Y]2−; Xi, Ya = Cl, Br; with AgNO3 in ethanol/dichloromethane and addition of NaN3 the octa-μ3-halogeno-hexazido-octahedro-hexamolybdate(2−) anions [(Mo6X)(N3)]2− are formed. X-ray structure determinations have been performed on single crystals of (n-Bu4N)2[(Mo6Cl)(N3)] (1) (monoclinic, space group P 21/n, a = 14.592(5) A, b = 12.314(5) A, c = 17.039(5) A, β = 101.183(5)°, Z = 2), (n-Bu4N)2[(Mo6Br)(N3)] (2) (monoclinic, space group P 21/n, a = 14.595(6) A, b = 12.416(5) A, c = 16.960(3) A, β = 100.74(3)°, Z = 2) and (Ph3PNPPh3)2 [(Mo6Br)(N3)] (3) (triclinic, space group P 1, a = 11.092(4) A, b = 13.161(8) A, c = 14.341(11) A, α = 78.085(6)°, β = 82.821(5)°, γ = 84.379(4)°, Z = 1). Whereas the cluster anions of the (n-Bu4N) salts reveal a regular geometry, the (Ph3PNPPh3) cation causes strong distortions of the cluster kernel with variation of the Mo–Mo and Mo–Bri distances up to 8%. Using the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) cluster salts are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are fd(MoMo) = 1.53 (Cli), 1.46 (Bri), fd(MoCli) = 1.09, fd(Mo–Bri) = 0.96, fd(Mo–N1) = 2.09 (Cli), 2.36 (Bri) mdyne/A, respectively.

Bei der Umsetzung von [(Mo6X)I]2−; Xi = Cl, Br, mit AgNCO in Aceton entstehen die Hexaisocyanato-Derivate [(Mo6Cl)(NCO)]2− und [(Mo6Br)(NCO)]2−, mit AgNO3 und anschliesender Zugabe von KNCSe die Hexaisoselenocyanate [(Mo6Cl)(NCSe)]2− und [(Mo6Br)(NCSe)]2−. Die Rontgenstrukturanalysen an Einkristallen von (TBA)2[(Mo6Cl)(NCO)](1) (triklin, Raumgruppe P1, a = 12,006(5), b = 12,084(5), c = 12,143(5) A, α = 61,974(5)°, β = 75,975(5)°, γ = 76,527(5)°, Z = 1), (TBA)2[(Mo6Br)(NCO)](2) (triklin, Raumgruppe P1, a = 11,880(5), b = 11,972(5), c = 12,107(5) A, α = 78,021(5)°, β = 78,320(5)°, γ = 62,660(5)°, Z = 1). (TBA)2[(Mo6Cl)(NCSe)] · 2Et2O (3) (monoklin, Raumgruppe P21/n, a = 11,30(2), b = 16,472(4), c = 20,134(3) A, β = 95,43(3)°, Z = 2) und (TBA)2[(Mo6Br)(NCSe)] · 2Me2CO (4) (triklin, Raumgruppe P1, a = 11,014(2), b = 12,72(2), c = 13,323(1) A, α = 78,48(2)°, β = 81,92(1)°, γ = 83,11(4)°, Z = 1) zeigen, das uber N gebundene Cyanat- und Selenocyanat-Gruppen vorliegen. Die (MoNC)-Bindungswinkel betragen 160,3° (1), 153,8–155,5° und 168,1° (2), 166,1° und 172,6° (3) sowie 172,9° und 147,1–165,1° (4), was fur (2), (3) und (4) auf die Ausbildung apikaler und aquatorialer Ligandengruppen hinweist. Unter Verwendung der rontgenographisch ermittelten Molekulparameter werden die bei 10 K registrierten IR- und Raman-Spektren der (TBA)-Clustersalze durch Normalkoordinatenanalysen auf der Basis eines modifizierten Valenzkraftfeldes zugeordnet. Die (MoN)-Valenzkraftkonstanten betragen 2,44 (1), 2,45 (2), 2,02 (3) und 1,92 mdyn/ A (4). Synthesis, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of (TBA)2[(Mo6X)Y]; Xi = Cl, Br; Ya = NCO, NCSe By treatment of [(Mo6X)I]2−, Xi = Cl, Br with AgNCO in acetone the hexaisocyanato derivates [(Mo6Cl)(NCO)]2− and [(Mo6Br)(NCO)]2− are formed, whereas the reaction with AgNO3 and KNCSe yields [(Mo6Cl)(NCSe)]2− and [(Mo6Br)(NCSe)]2−. The X-ray structure determinations on single crystals of (TBA)2[(Mo6Cl) (NCO)] (1) (triclinic, space group P1, a = 12.006(5), b = 12.084(5), c = 12.143(5) A, α = 61.974(5)°, β = 75.975(5)°, γ = 76.527(5)°, Z = 1), (TBA)2[(Mo6Br) (NCO)] (2) (triclinic, space group P1, a = 11.880(5), b = 11.972(5), c = 12.107(5) A, α = 78.021(5)°, β = 78.320(5)°, γ = 62.660(5)°, Z = 1), (TBA)2[(Mo6Cl) (NCSe)] · 2 Et2O (3) (monoclinic, space group P21/n, a = 11.30(2), b = 16.472(4), c = 20.134(3) A, β = 95.43(3)°, Z = 2) and (TBA)2[(Mo6Br) (NCSe)] · 2 Me2CO (4) (triclinic, space group P1, a = 11.014(2), b = 12.72(2), c = 13.323(1) A, α = 78.48(2)°, β = 81.92(1)°, γ = 83.11(4)°, Z = 1) reveal that the cyanate and selenocyanate groups are coordinated via the N atoms. The (MoNC) angles are 160.3° (1), 168.1° and 153.8–155.5° (2), 166.1° and 172.6° (3), 172.9° and 147.1–165.1° (4), indicating apical and equatorial groups of ligands in (2), (3), (4). Using the molecular parameters of the X-ray determinations the low temperature (10 K) IR and Raman spectra of the (TBA) cluster salts are assigned by normal coordinate analyses based on a modified valence force field. The (MoN) valence force constants are 2.44 (1), 2.45 (2), 2.02 (3), 1.92 mdyne/ A (4).

Bei der Umsetzung von cis- oder trans-[OsCl4I2]2− mit (SCN)2 in Dichlormethan entstehen die Bindungsisomeren cis-[OsCl4(NCS)2]2− (1), trans-[OsCl4(NCS) · (SCN)]2− (2), cis-[OsCl4(NCS)(SCN)]2− (3) und trans-[OsCl4 · (SCN)2]2− (4), die durch Ionenaustauschchromatographie an Diethylaminoethyl-Cellulose getrennt werden. Die Rontgenstrukturanalysen an Einkristallen von cis-(Ph4As)2[OsCl4(NCS)2] (triklin, Raumgruppe P1, a = 10,019(5), b = 11,702(5), c = 21,922(5) A, α = 83,602(5)°, β = 85,718(5)°, γ = 73,300(5)°, Z = 2), trans-(Ph4As)2[OsCl4(NCS)(SCN)] (monoklin, Raumgruppe P21/c, a = 18,025(5), b = 11,445(5), c = 23,437(5) A, β = 94,208(5)°, Z = 4), cis-(Ph4As)2[OsCl4(NCS)(SCN)] (triklin, Raumgruppe P1, a = 10,579(5), b = 11,682(5), c = 22,557(5) A, α = 81,073(5)°, β = 85,807(5)°, γ = 87,677(5)°, Z = 2) und trans-(Ph4As)2[OsCl4(SCN)2] (triklin, Raumgruppe P1, a = 10,615(5), b = 11,691(5), c = 11,907(5) A, α = 111,314(5)°, β = 96,718(5)°, γ = 91,446(5)°, Z = 1) zeigen, das die Komplexanionen in allen vier Verbindungen vollig geordnet vorliegen. Die uber N bzw. S gebundenen Thiocyanatgruppen sind unter OsNC-Winkeln von 171,2° und 174,3° (1), 162,3° (2), 172° (3) bzw. unter OsSC-Winkeln von 108,3° (2), 105,7° (3) sowie 105.5° (4) nahezu auf Deckung uber einem cis-standigen Cl-Liganden angeordnet. Unter Verwendung der rontgenographisch ermittelten Molekulparameter lassen sich die an (n-Bu4N)-Salzen bei 10 K aufgenommenen IR- und Raman-Spektren der vier Bindungsisomeren durch Normalkoordinatenanalysen auf der Basis eines modifizierten Valenzkraftfeldes zuordnen. Die Valenzkraftkonstanten betragen fur fd(OsN) = 1,59 (1), 1,67 (2), 1,60 (3), fur fd(OsS) = 1,27 (2), 1,31 (3) und 1,32 mdyn/A (4). Bei Berucksichtigung von Inkrementen des trans-Einflusses ergibt sich eine gute Ubereinstimmung zwischen beobachteten und berechneten Frequenzen. Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl4I2]2− with (SCN)2 in dichloromethane the linkage isomers cis-[OsCl4(NCS)2]2− (1), trans-[OsCl4(NCS)(SCN)]2− (2), cis-[OsCl4(NCS)(SCN)]2− (3) and trans-[OsCl4(SCN)2]2− (4) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph4As)2[OsCl4(NCS)2] (triclinic, space group P1, a = 10.019(5), b = 11.702(5), c = 21.922(5) A, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph4As)2[OsCl4 · (NCS)(SCN)] (monoclinic, space group P21/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) A, β = 94.208(5)°, Z = 4), cis-(Ph4As)2[OsCl4(NCS)(SCN)] (triclinic, space group P1, a = 10.579(5), b = 11.682(5), c = 22.557(5) A, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph4As)2 · [OsCl4(SCN)2] (triclinic, space group P1, a = 10.615(5), b = 11.691(5), c = 11.907(5) A, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with OsNC angles of 171.2° and 174.3° (1), 162.3° (2), 172° (3) and OsSC angles of 108.3° (2), 105.7° (3) and 105.5° (4). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu4N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are fd(OsN) = 1.59 (1), 1.67 (2), 1.60 (3) and fd(OsS) = 1.27 (2), 1.31 (3) and 1.32 mdyn A−1 (4). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.

Es wird uber die Darstellung der Pnikogenoniumsalze AsH4+SbF6−, AsH4+AsF6− und SbH4+SbF6− aus AsH3 bzw. SbH3 durch Protonierung in den supersauren Systemen HF/SbF5 bzw. HF/AsF5 berichtet. Ihre Charakterisierung erfolgt schwingungsspektroskopisch und durch Massenspektren. Aus den Schwingungsfrequenzen wurden fur AsH4+ und SbH4+ Kraftfelder (GVFF) berechnet. Damit sind folgende Oniumionen als Hexafluoroantimonate bekannt: . On the Preparation of Pnikogenonium Salts AsH4+SbF6−, AsH4+AsF6−, SbH4+SbF6− The preparation of the pnikogenonium salts AsH4+SbF6−, AsH4+AsF6− and SbH4+SbF6− by protonation from the hydrides AsH3, SbH3 in superacidic systems HF/SbF5 and HF/AsF5, resp. is reported. The salts are characterized by vibrational and mass spectra. A general valence force field is calculated. The following onium ions are know as hexafluoroantimonate

[TcX6]2−, X = Cl,Br, reagiert bei Raumtemperatur mit Trifluoressigsaure unter Bildung der kantenverknupften Dioktaederanionen [Tc2X10]2−, deren IR- und Raman-Spektren entsprechend der Punktgruppe D2h zugeordnet werden. Basierend auf den kristallographischen Daten isostruktureller Osmiumkomplexe und unter Verwendung des allgemeinen Valenzkraftfeldes, werden fur Decachloro- und Decabromodi-technetat(IV) Normalkoordinatenanalysen durchgefuhrt, die eine gute Ubereinstimmung der berechneten Frequenzen mit den beobachteten Banden aus den IR- und Raman-Spektren ergeben. Die festere Bindung terminaler im Vergleich zu verbruckenden Liganden spiegelt sich in den Valenzkraftkonstanten wider: fd(TcXt) > fd(TcXb). Preparation, Vibrational Spectra and Normal Coordinate Analysis of Decahalogenoditechnetates(IV), [Tc2X10]2−, X = Cl, Br The reaction of [TcX6]2−, X = Cl, Br, with trifluoroacetic acid yield at room temperature the edge-sharing bioctahedral anions [Tc2X10]2−, which IR and Raman spectra are assigned according to point group D2h. Using the crystal data of isostructural osmium complexes a normal coordinate analysis based on a general valence force field has been performed for [Tc2X10]2−, revealing a good agreement of the calculated frequencies with the bands observed in the IR and Raman spectra. The stronger bonding of the terminal as compared to the bridging ligands is shown by the valence force constants, fd(TcXt) > Fd(TcXb).

Die an 8 Komplexen des Typs [ReX.Y4Z′]2−, C4v, X. = F, Cl, Br, I; Y = Cl, Br, I; Z' = Cl, Br, I, auf der Grundlage des allgemeinen Valenzkraftfeldes durchgefuhrten Normalkoordinatenanalysen zeigen, das die Kraftfelder in sehr guter Nahrung durch charakteristische Beitrage der Baugruppen ReY4-Ebene, trans-gelockerte ReX.- und trans-gefestigte ReZ′-Bindung beschrieben werden konnen. Fur die ReY4-Ebene gelten die gleichen Valenzkraftkonstanten wie fur die homoleptischen Spezies [ReY6]2, Oh (F = 3,23, Cl = 1,67, Br = 1,33, I = 0,80 mdyn/A). An den unsymmetrischen Achsen X.ReZ′ bewirkt der in der Reihe F < Cl < Br < I zunehmende trans-Einflus wechselseitig die Erniedrigung der Kraftkonstanten fur ReX.-Bindungen um bis zu 10% im Fall ReF. und eine Erhohung fur ReZ′-Bindungen um bis zu 15% fur ReI′. Unter Verwendung der fur die Baugruppen ermittelten Daten lassen sich die Schwingungsfrequenzen fur die verschiedenen gemischten Halogenorhenate(IV) mit einer Zuverlassigkeit von wenigen cm−1 berechnen. Normal Coordinate Analysis on Heteroleptic Hexahalorhenates(1V) with Point Symmetry C4v Normal coordinate analyses, based on a general valence force field, for 8 complexes [ReX.Y4Z′]2−, C4v, X. = F, Cl, Br, I; Y = Cl, Br, I; Z′ = Cl, Br, I, reveal that the force fields may be well approximated by characteristic structural elements: ReY4 plane, trans-weakened ReX. and trans-strengthened ReZ′ bonds. For the ReY4 plane the same valence force constants are valid as for the homoleptic species [ReY6]2− (F = 3.23, Cl = 1.67, Br = 1.33, I = 0.80 mdyn/A). Due to the increasing trans influence F < Cl < Br < I for asymmetric axes X.ReZ′ the force constants are mutual lowered at ReX. bonds, up to 10% in case of ReF., and enhanced at ReZ′ bonds up to 15% for ReI′. Using the data determined for the structural groups the vibrational frequencies of different mixed halorhenates(IV) can be calculated with reliability of a few cm−1.

Methoxy(oxy)sulfonium-hexafluoroarsenat CH3OSO+ AsF kristallisiert in der monoklinen Raumgruppe P21/n mit a = 547,0(4) pm, b = 1 728,1(5) pm, c = 767,8(4) pm, β = 106,69(4)°, Z = 4. Das Kation ist planar mit Bindungsabstanden von d(CO) = 150,2(9) pm, d(SO) = 150,5(5) pm, d(SO) = 139,7(5) pm und Winkeln ∢ (COS) = 125,8(4)°, ∢ (OSO) = 114,9(3)°. Die Schwingungsfrequenzen des Kations werden unter Einbeziehung der 34S und 18O markierten Spezies diskutiert. Eine Kraftfeldberechnung ergibt f(CO) = 3,75 Ncm−1, f(SO) = 6,91 Ncm−1, f(SO) = 10,81 Ncm−1. Crystal Structure, Vibrational Spectra, and Valence Force Field of Methoxy(oxy)-sulfonium Hexafluoroarsenate CH3OSO+ AsF Methoxy(oxy)sulfonium hexafluoroarsenate CH3OSO+ AsF crystallizes in the monoclinic space group P21/n with a = 547,0(4) pm, b = 1 728.1(5) pm, c = 767.8(4) pm, β = 106.69(4)°, Z = 4. The cation is planar with bond distances d(CO) = 150.2(9) pm, d(SO) = 150.5(5) pm, d(SO) = 139.7(5) pm and angles ∢ (COS) = 125.8(4)°, ∢ (OSO) = 114.9(3)°. The vibrational frequencies of the cation are discussed with correspondence to the values of 34S and 18O labelled substituted species. A force field calculation equates f(CO) = 3.75 Ncm−1, f(SO) = 6.91 Ncm−1, f(SO) = 10.81 Ncm−1.

A method is presented by which ab initio (or empirical) force fields and structures can be converted to molecular mechanics energy parameters. Using Cartesian coordinates, the effect of van der Waals and other nonquadratic interactions is eliminated from the original spectroscopic force field, and molecular mechanics force constants and reference geometry parameters are derived. The computed parameters yield molecular structure and vibrational frequencies that are identical to the original ones. The transformation produces a complete general valence force field, which in most cases is impractical, and a procedure to reduce the number of force constants is therefore described. Different ways of applying the transformation are outlined.

The Raman spectra of liquid (CH 3 ) 4−m Si(CD 3 ) m (m=0-4), (CH 2 D) 4−n Si(CH 3 ) n and (CHD 2 ) 4−n Si(CD 3 ) n (n=0-3) were recorded from 3200 to 50 cm −1 . Normal coordinate analyses were made using both a unique internal valence force field (IVFF 1) for all 13 isotopomers and 13 slightly modified IVFF 2s for each isotopomer, including torsional modes in each case. Vibrational assignments were made using the potential energy distributions and eigenvectors in addition to the depolarization ratios, the IR spectra and the Teller-Redlich product rule

The Raman and infrared spectra of N,N-diethylformamide, N,N-diethylacetamide, N,N-diethylchloroacetamide and N,N-diethylpropionamide were measured. Raman polarization measurements were also made. A normal coordinate analysis was carried out for N,N-diethylformamide, N,N-diethylacetamide and N,N-diethylchloroacetamide using a 63-parameter modified valence force field. The force constants were refined in an overlay least-squares technique using vibrational frequencies of the molecules to obtain a converged set of meaningful force constants. The reliability of the force constants so obtained was tested by making a zero-order calculation for N,N-diethylpropionamide. The potential energy distributions and eigenvectors calculated in the process were used to make unambiguous vibrational assignments.

The lattice dynamics of alkali metals is investigated on the basis of a phenomenological model which is consistent with the translational symmetry of a lattice. The potential energy is considered due to (1) ion-ion and (2) ion-electron interactions. The contribution to ion-ion interaction is evaluated applying the valence force field. The contribution to the potential energy from ion-electron interaction is considered through the screened Coulomb potential. The theoretical model developed is employed to compute the phonon dispersion curves of Na, K, Li, Rb, and Cs. Computed phonon frequencies are used to interpret the Debye characteristic temperatures at different temperatures. The calculated results for phonon dispersion curves and Debye characteristic temperatures compare well with the experimental ones. Die Gitterdynamik von Alkalimetallen wird auf der Grundlage eines phanomenologischen Modells untersucht, das mit der Translationssymmetrie eines Gitters konsistent ist. Die potentielle Energie wird in Form von (1) Ion-Ion- und (2) Ion- Elektron-Wechselwirkung berucksichtigt. Der Beitrag der Ion-Ion-Wechselwirkung wird durch Benutzung des Valenzkraftfelds berechnet. Der Beitrag zur potentiellen Energie aus der Ion-Elektron-Wechselwirkung wird durch ein abgeschirmtes Coulombpotential berucksichtigt. Das entwickelte theoretische Modell wird benutzt, um die Phonondispersionskurven von Na, K, Li, Rb und Cs zu berechnen. Die berechneten Phononenfreqiemzem werden benutzt, um die charakteristischen Debye-Temperaturen bei verschiedenen Temperaturen zu interpretieren. Die berechneten Ergebnisse fur die Phononendispersionskurven und die charakteristischen Debye-Temperaturen stimmen gut mit experimentellen Ergebnissen uberein.

Aus wasrig saurer Losung von [RhCl6]3− fallt nach dem ersten Hydrolyseschritt in Gegenwart von Cs+-Ionen nahezu quantitativ Cs2[RhCl5(H2O)], aus [RhCl5Br]3−-Losung stereospezifisch entstandenes trans-Cs2[RhCl4Br(H2O)] aus. Die orangenen Cs-Salze dieser Monaquo-Komplexe losen sich nur masig in Wasser und sind in organischen solventien unloslich. Die entsprechend der Punktgruppe C4v getroffene Zuordnung der IR- und Raman-Spektren wird durch eine Normalkoordinatenanalyse auf der Grundlage eines allgemeinen Valenzkraftfeldes bestatigt. Die beobachteten und berechneten Frequenzen stimmen sowohl im Valenz- als auch im Deformationsschwingungsbereich gut uberein. Als Folge des in der Reihe H2O, Cl−, Br− zunehmenden trans-Einflusses sind die Bindungen der dem Wasser gegenuberstehenden Liganden gefestigt. Die Valenzkraftkonstante der axialen RhCl-Bindung ist um 10% groser als die der aquatorialen in Cs2[RhCl5(H2O)], die von RhBr in Cs2[RhCl4Br(H2O)] liegt um 25% uber der in [RhBr6]3−. Preparation, Vibrational Spectra, and Normal Coordinate Analysis of Cs2[RhCl5(H2O)] and trans-Cs2[RhCl4Br(H2)] In a first step of hydrolysis of [RhCl6Br]3− in aqueous acidic solution [RhCl5(H2O)]2− and stereospecifically trans-[RhCl4Br(H2O)]2− are formed nearly quantitatively, precipitating in presence of Cs+ ions. The orange Cs-salts of the monoaquo complexes are slightly soluble in water and insoluble in organic solvents. The IR and Raman spectra are completely assigned according to point group C4v, supported by normal coordinate analysis based on a general valence force field. The observed and calculated frequencies are in good agreement for the stretching and deformation vibrations. The trans-influence increases in the series H2O, Cl−, Br−. The valence force constant of the axial RhCl-bond exceeds that of the equatorial bonds in Cs2[RhCl5(H2O)] by 10%, the RhBr valence force constant in tr.-Cs2[RhCl4Br(H2O)] that of [RhBr6]3 by 25%.

Die Raman-Spektren der durch Umsetzung von Os16O4 und Os18O4 mit BCl3 dargestellten Isotopomeren Os16OCl4 und Os18OCl4 zeigen starke Isotopenverschiebungen fur die OsO-Valenzschwingung v1(A1) von 1 026 auf 973 cm−1 und fur die OOsCl-Deformationsschwingung v8(E) von 264 auf 253 cm−1. Fur die vollstandige Zuordnung aller beobachteten Frequenzen sind Polarisationsmessungen und eine Normal-koordinatenanalyse auf der Grundlage des allgemeinen Valenzkraftfeldes durchgefuhrt worden. Raman Spectra and Normal Coordinate Analysis of the 16O and 18O Isotopomeres of Tetrachlorooxoosmium(VI), OsOCl4 The Raman spectra of the isotopomers Os16OCl4 and Os18OCl4 prepared by reaction of Os16O4 and Os18O4 with BCl3 exhibit strong isotopic shifts of the OsO stretching frequency v1(A1) from 1 026 to 973 cm−1 and of the OOsCl bending vibrations v8(E) from 264 to 253 cm−1. The complete assignment of all observed frequencies is achieved by polarization measurements and a normal coordinate analysis based on the general valence force field.

Beim Erhitzen des Tetraethylammonium-Salzes (TEA)2[TcBr6] mit Trifluoressigsaure entsteht das flachenverknupfte Bioktaederanion [Tc2Br9]−, dessen Schwingungsspektrum entsprechend der Punktgruppe D3h zugeordnet wird. Die auf der Grundlage des allgemeinen Valenzkraftfeldes durchgefuhrte Normal-koordinatenanalyse ergibt eine gute ubereinstimmung der berechneten Frequenzen mit den beobachteten IR-und Raman-Banden. Wegen der festeren Bindung der terminalen im Vergleich zu verbruckenden Liganden ist die Valenzkraftkonstante fd(TcBrt) = 1,045 deutlich groser als fd(TcBrb) = 0,80 mdyn/A. Preparation, Spectroscopic Characterization and Normal Coordinate Analysis of Nonabromoditechnetate(IV), [Tc2Br9]−. On heating the tetraethylammonium salt (TEA)2[Tc2Br6] with trifluoroacetic acid the face-sharing bioctahedral anion [Tc2Br9]− is formed, which vibronic spectrum is assigned according to point group D3h. Normal coordinate analysis, based on a general valence force field has been performed, resulting in a good agreement of calculated frequencies with the observed IR and Raman bands. Due to stronger bonding of the terminal as compared to the bridging ligands, the valence force constant fd(TcBrt) = 1.045 is significantly higher than fd(TcBrb) = 0.80 mdyn/A.

Es werden die Schwingungsspektren (IR und RAMAN) von OPF2(OCH3), OPF(OCH3)2, SPF2(OCH3) und SPF(OCH3)2 mitgeteilt und die Zuordnung zu den Grundschwingungen vorgenommen. Nach einem Naherungsverfahren werden die Valenzkraftkonstanten berechnet und die Bindungsverhaltnisse diskutiert. Vibrational Spectra and Force Constants of the Series OPF3OP(OCH3)3 and SPF3SP(OCH3)3 The vibrational spectra (IR and RAMAN) for OPF2(OCH3), OPF(OCH3)2, SPF2(OCH3) and SPF(OCH3)2 are reported and assigned to the normal vibrations. The valence force constants are calculated by a simplified valence force field. The changes of the bonds are discussed.

The FT-IR spectra of the [Cl2FeS2MoS2FeCl2]2− dianion were measured in the range 500 to 100 cm−1. A simplified general valence force field was used in a normal coordinate analysis. The calculated frequencies agree well with the observed values, with a mean deviation of less than 1.0%, thus confirming the assignments of the vibrational spectrum. Altogether 16 force constants, including stretching, bending, torsion and stretching-stretching interactions were obtained. The rationality and the reliability of the results were discussed.

Normal coordinate calculations have been performed for poly(vinylidene chloride) employing a TXTX′ conformational model (X and X′ denote torsional angles of equal value but opposite sign). A valence force field previously determined from the model compounds 2,2-dichloropropane and 2,2-dichlorobutane was directly transferred to the chain conformation of the polymer. The results are in excellent agreement with the observed vibrational spectra and we have been able to satisfactorily assign all the major normal modes.

Bei der UV-Photolyse von CF3SF3 bzw. CF3SeF3 in Ar-Matrix entsteht in hohen Ausbeuten SF2 bzw. SeF2. Durch dieses neue Darstellungsverfahren war es moglich, von SeF2 die noch unbekannte Deformationsschwingung v2 zu vermessen und ein allgemeines Valenzkraftfeld (GVFF) zu berechnen. Aus der Korrelation zwischen Bindungslangen und Valenzkraftkonstanten von SeF-Verbindungen kann die Bindungslange im SeF2 zu 172,5 pm abgeschatzt werden. Der Einflus der Matrixumgebung auf die Schwingungsfrequenzen des SF2 und SeF2 wird diskutiert. Lower Chalcogen Fluorides. VII. Formation of SF2 and SeF2 in Ar Matrix by U. V. Photolysis The u.v. photolysis of CF3SF3 and CF3 isolated in Ar matrix leads to SF2 and SeF2 respectively. Due to this new synthesis it was possible to measure the unknown deformation mode v2 of SeF2 and to calculate a general valence force field (GVFF). A bond length of 172.5 pm was derived for SeF2 from a relationship between valence force constants and bond lengths of SeF compounds. The influence of the matrix on the vibrational frequencies in SF2 and SeF2 is discussed.

The present paper gives a survey over applications of vibrational spectroscopy — especially RAMAN methods — in inorganic chemistry. The following topics are covered: analytical application for the characterisation of molecular compounds, their symmetry and structure, discussion of bond properties by means of Valence Force Field methods, effects of intermolecular interactions on the spectra of liquids and solids. The importance of intensity calculations for the check and improvement of force field calculations is briefly referred to. These different aspects of RAMAN spectroscopy are introduced using examples from recent literature and from the current work of the author.

Infrared absorption and polarized Raman spectra of rare-earth titanates of pyrochlore structure Ln2Ti2O7 (Ln = Sm, Gd, Yb; Y) and Ln2Sn2O7 (Ln = La, Sm, Gd, Yb, Lu; Y) have been recorded. A valence force field calculation clearly supports the assignment of the frequencies. A comparison of the results with those of homologous zirconates and hafnates is presented.

Auf der Basis eines modifizierten Valenzkraftmodells werden die Kraftkonstanten, Eigenvektoren und Schwingungsformen der Chromthiospinelle ACr2S4 (A = Zn, Cd, Hg, Mn, Fe, Co) berechnet. Die beste Ubereinstimmung zwischen den beobachteten und berechneten Frequenzen der 4 IR-aktiven Schwingungen des Spinellgitters ergibt ein Potentialmodell mit den 2 Bindungskraftkonstanten fAS und fCrS, der Wechselwirkungskonstante zwischen diesen beiden Bindungen und einer der beiden Winkeldeformationskraftkonstanten ΔφSCrS und ΔφSAS. Die Cr – S-Bindungskraftkonstante ist entsprechend dem groseren Abstand zwischen dem Schwefel und dem oktaedrisch koordinierten Chrom im Vergleich mit dem Bindungsabstand im AS4-Tetraeder deutlich kleiner als die A – S-Bindungskraftkonstante. Die Wechselwirkungs- und die Winkeldeformationskonstanten sind positiv und konnen nicht vernachlassigt werden. Die Normalkoordinatenrechnung ergibt, das an jeder der 4 IR-aktiven Schwingungen alle Atome der Basiszelle beteiligt sind. Es zeigen sich jedoch signifikante Unterschiede bei der Beteiligung der 5 Symmetriekoordinaten an den verschiedenen Schwingungen. Force constants, eigenvectors and vibrational modes of the chromium thiospinels ACr2S4 (A = Zn, Cd, Hg, Mn, Fe, Co) are calculated based on the frequencies of the four ir-active vibrations of the spinel lattice. Best agreement of the observed and calculated frequencies is reached with a modified short range valence force field consisting of an A – S- and a Cr – S-bond stretching constant, the interaction constant between these two bonds and the ΔφSAS or ΔφSCrS bond bending force constant. According to the longer distance between sulfur and the octahedral coordinated chromium atoms compared with the bond length in the AS4-tetrahedron the Cr – S-stretching constant is much smaller than the A – S-stretching constants. The interaction constant and the bond bending force constants are positive and not negligible. The results of the normal coordinate calculations show that all atoms of the unit cell contribute to each one of the four vibrations of species F1u but there are significant differences according to the contribution of the 5 symmetry coordinates to the 4 ir-active vibrations.

The infrared and Raman spectra (600 to 10 cm−1) of polycrystalline samples and of single crystals of HfS3 are investigated. A complete assignment is proposed and the frequencies of normal modes in HfS3, ZrS3, and TiS3 are compared. Resonance Raman spectra of HfS3 are recorded using a variety of Kr+, Ar+, and stilbene-3 dye-laser lines (647.1 to 431.2 nm) within the contour of the lowest allowed excitonic transitions. In agreement with previous studies on ZrS3, the unresolved excitation profiles are well accounted for by a Franck-Condon scattering mechanism in which several modes and several interfering electronically excited states are involved. Finally, a valence force field with intrachain, interchain, and interlayer contributions is proposed: the potential energy distributions and mean square vibrational amplitudes are computed and the force-constant values are compared in HfS3 and ZrS3 compounds. It is concluded that the lattice dynamics are governed by the two-dimensional or layer-type character of these MS3 systems. Die Infrarot- und Ramanspektren (600 bis 10 cm−1) von polykristallinen Proben und Einkristallen von HfS3 werden untersucht. Eine vollstandige Zuordnung wird vorgeschlagen und die Frequenzen der Normalmoden in HfS3, ZrS3 und TiS3 werden verglichen. Resonanzramanspektren von HfS3 werden aufgenommen, wobei eine Vielzahl von Kr+, Ar+ und Stilben-3-Farblaserlinien (647,1 bis 431,2 nm) im Bereich der tiefsten erlaubten Exzitonenubergange benutzt wird. In Ubereinstimmung mit fruheren Untersuchungen an ZrS3, lassen sich die unaufgelosten Anregungsprofile durch einen Franck-Condon-Streumechanismus erklaren, an dem einige Moden und interferierende angeregte elektronische Zustande beteiligt sind. Schlieslich wird ein Valenzkraftfeld mit Intraketten-, Interketten- und Interschicht-Beitragen vorgeschlagen: die Verteilung der potentiellen Energie und die Mittelwerte der Schwingungsamplituden werden numerisch berechnet und die Werte der Kraftkonstante in HfS3- und ZrS3-Verbindungen verglichen. Es wird angenommen, das die Gitterdynamik durch den zweidimensionalen oder den schichtartigen Charakter dieser MS3-Systeme gesteuert wird.

The Raman spectra of gaseous, liquid and solid CH3PF2 and the infrared spectra of the gas and solid have been recorded (3200–20 cm−1). The assignment of the 15 fundamentals is given and discussed and is based on the gas phase infrared band contours, depolarization values and group frequencies. A normal coordinate calculation was carried out by utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. Extensive mixing was found between the PF2 stretching and CH3 rocking modes. The methyl torsion was observed at 192 cm−1 in the far-infrared spectrum of the gas and from this frequency a three-fold barrier to internal rotation of 1.74 kcal mol−1 was calculated. This value is compared to similar quantities in several other group VA compounds and the observed trends are consistent with those for the corresponding group IVA compounds.

Die IR- und Ramanspektren der monomeren Hexamethoxide des Wolframs und Molybdans sowie des ionischen [Me4Sb]+[Sb(OMe)6]− (dargestellt aus [Sb(OMe)5]2 und Me4SbOMe; Me = CH3) werden aufgenommen und der Punktgruppe C3i zugeordnet. Kraftkonstantenrechnungen fur W(OMe)6 und fur [Sb(OMe)6]− ergeben praktisch identische WO- und SbO-Valenzkraftkonstanten (2,56 N/cm), dagegen sind die ubrigen Kraftkonstanten signifikant verschieden. Vibrational Spectra and Force Constants of W(OCH3)6, Mo(OCH3)6, and [Sb(CH3)4][Sb(OCH3)6] The infrared and Raman spectra of the monomeric hexamethoxides of Tungsten and Molybdenum and of the ionic compound [Me4Sb]+[Sb(OMe)6]− (prepared from [Sb(OMe)5]2 and Me4SbOMe; Me = CH3) are recorded and interpreted on the basis of C3i symmetry. The force fields of W(OMe)6 and [Sb(OMe)6]− are calculated using the same basis set of force constants. Both WO- and SbO- stretching force constants are identical (2.56 N/cm), however the other parts of the valence force field are markedly different.

The Raman and infrared spectra of poly(dA) · poly(dT) and poly(dAT) · poly(dAT) have been recorded. Normal coordinate analyses have been performed for these two polymers to obtain the fundamental modes. We use a valence force field deduced from literature values and from a refinement of a diethyl phosphate potential. Non-bonded interactions are not included. Extensive descriptions of each mode are given allowing qualitative understanding of some of the spectral difference found between the two polymers.

Die IR- und Ramanspektren des flussigen Diathylzinks wurden Vermessen, empirisch zugeordnet und mit den mittels eines von Dimethylzink und Dimethylzink-d6 ubernommenen modifizierten Valenzkraftfeldes berechneten Schwingungsfrequenzen und -formen Verglichen. Vibrational Spectra and Normal Coordinate Analysis of Dimethylzinc, Dimethylzinc-d6, and Diethylzinc The IR and Raman spectra of Diethylzinc have been recorded, assigned empirically, and compared with the vibrational frequencies and forms calculated and forms calculated by means of a modified valence force field transferred from Dimethylzinc.

Fur die Kationen (CH3)3NCl+ (1), (CH3)3PCl+ (2), (CH3)3AsCl+ (3) und (CH3)3SbCl+ (4) werden nach dem Kopplungsstufenverfahren unter Verwendung eines allgemeinen Kraftfeldes Normalkoordinatenanalysen durchgefuhrt. Die erhaltenen Kraftkonstanten werden kurz diskutiert. Berechnungen der Potentialenergieverteilung zeigen, das bei 4 alle Gerustschwingungen charakteristisch sind, bei 1 jedoch starke Schwingungskopplung auftritt. Force Constants of Compounds of the Type (CH3)3ElCl+X−(El = N, P, As, Sb; X− = SbCl6−) For the cations (CH3)3NCl+ (1), (CH3)3PCl+ (2), (CH3)3AsCl+ (3), and (CH3)3SbCl+ (4) a normal coordinate analysis using a general valence force field is performed by the method of Fadini. The force constants are discussed. Calculations of the potential energy distribution show, that the skeletal vibrations in 4 are all characteristic vibrations, but there is a strong coupling of vibrations in 1.

Es werden die IR-Spektren von A2BYF6 (A = K, Rb, Cs; B = Na, K, Rb, Cs) mitgeteilt und daraus mittels eines modifizierten Valenzkraftfeldes funf Kraftkonstanten berechnet. Die Ergebnisse werden fur die beiden Bindungsarten diskutiert. IR Spectra and Forcefields of Ternary Alkali–Yttrium Fluorides with Elpasolite Structure IR spectra of A2BYF6 are reported and five force constants are calculated using a modified valence force field. The results are discussed with respect to the two bond characters.

A theoretical model for the lattice dynamics of b.c.c. metals is develoed. Contribution to ion-ion interaction is evaluated applying the valence force field. The contribution to the potential energy from ion-electron interaction is considered by a screened Coulomb potential. Computed phonon dispersion curves and Debye characteristic temperatures for α-iron and tungsten on the basis of the model compare well with the experimental results. The Cauchy discrepancy is expressed in terms of an angle-dependent potential energy in the present model. Es wird ein theoretisches Modell fur die Gitterdynamik der k.r.z. Metalle entwickelt. Durch Anwendung des Valenzkraftfeldes wird der Beitrag der Ionen-Ionen-Wechselwirkung berechnet. Der Beitrag der Ionen-Elektronenwechselwirkung zur Potentialenergie wird durch ein abgeschirmtes Coulombpotential berucksichtigt. Die berechneten Phononendispersionskurven und die charakteristischen Debye-Temperaturen fur α-Eisen und Wolfram auf der Basis des Modells stimmen gut mit experimentellen Ergebnissen uberein. Die Cauchy-Diskrepanz wird im angegebenen Modell mit einer winkelabhangigen Potentialenergie ausgedrackt.

The Raman spectra of KOX (X H or D) at 77 K and room temperature are reported. The observed frequencies are assigned on the basis of a normal coordinate analysis by use of the valence force field. The KO stretching force constants are consistent with those expected from bond distances or related compounds. Dispersion relations are derived and some bands are assigned to a combination band at critical points.

The vibrational spectra of NaOX (X = H or D) at room temperature and 77 K are reported. A normal co-ordinate analysis has been carried out to assign the observed bands on the basis of the valence force field. The force constants were adjusted by considering a bond distance and reproduce well the observed frequencies. In the dispersion relations on k2 and kx the librational modes were found to be insensitive to k, whereas the translational modes except for the A1g and B1u modes vary considerably with k. Some bands were assigned to the combination band between a fundamental and an acoustic mode.

The vibrational excitations of the various fluorine hydrogen complexes, and the polysilane-like conformations in amorphous silicon are studied after employing a valence force field mode1 (VFFM) in a cluster Bethe lattice formulation. The calculated high frequencies are seen to be in excellent agreement with the infrared and Raman data. Some calculated peaks appearing at 214 and near 600 cm−1 have not been detected so far. More experimental measurements on a-Si : F : H alloys need to be performed especially in the low-frequency region ≈600 cm−1 to detect the predicted structure. Die Schwingungsanregungen der verschiedenen Fluor-Wasserstoffkomplexe und Polysilan-ahnlichen Gebilde in amorphem Silizium werden unter Anwendung eines Valenzkraft-Feldmodells (VFFM) in einer Cluster-Bethe-Gitterformulierung untersucht. Es wird gezeigt, das die berech-neten hohen Frequenzen in ausgezeichneter ubereinstimmung mit den Infrarot- und Raman-Daten sind. Einige berechnete Maxima bei 214 und ungefahr 600 cm−1 wurden bisher noch nicht nachgewiesen. Weitere experimentelle Untersuchungen an a-Si : F : H Legierungen sind insbesondere im Bereich niedrigerer Frequenzen bei ≈600 cm−1 notwendig, um die vorhergesagte Struktur nachzuweisen.

Die Infrarot- und Raman-Spektren von Cl3SiP(CH3)2 und Cl3SiAs(CH3)2 wurden aufgenommen und zugeordnet. Auf der Grundlage eines modifizierten Valenzkraftfeldes wurde eine Normalkoordinatenanalyse durchgefuhrt. Die SiP-Kraftkonstante liegt etwas hoher als in Alkylsilylphosphanen; fur die SiAs-Bindung wird eine solche Verstarkung nicht gefunden. Vibrational Spectra and Force Constants of Cl3SiP(CH3)2 and Cl3SiAs (CH3)2 The i.r. and Raman spectra of Cl3SiP(CH3)2 and Cl3SiAs (CH3)2 have been recorded and assigned. A normal coordinate analysis has been made using a modified valence force field. The SiP force constant is slightly higher than those of alkylsilylphosphines, whereas a similar effect is not found for the SiAs bond.

Die Elektronenabsorptionsspektren der Ionen VS43−, MoO222−, WO2S22 und ReO3S− in wasriger Losung werden mitgeteilt und diskutiert. Das Raman-Spektrum des VO43− Ions in Losung und das IR-Spektrum von (NH4)3VS4 wurden gemessen. Mit Hilfe der Lasertechnik konnten die Raman-Spektren der farbigen kristallinen Salze Cs2MoS4 (rot) und Cs2WS4 (gelb) aufgenommen werden. Kraftkonstanten eines allgemeinen und eines modifizierten Valenzkraftfeldes sowie des Urey-Bradley-Kraftmodells sind fur VO43−, VS43−, MoS42− und WS42− angegeben. Nach der L-Matrix-Methode von Morino wurden mittlere Schwingungsamplituden bei 298 °K fur diese lonen berechnet. Fur ReO3S− werden Kraftkonstanten unter Annahme einer diagonalen F-Matrix mitgeteilt. Die Valenzkraftkonstanten aller Ionen werden im Zusammenhang mit den Bindungsverhaltnissen diskutiert. The electron absorption spectra of the ions VS43−, MoO222−, WO2S22 and ReO3S− in aqueous solution are reported and discussed. The Raman spectrum of the VO3−4 ion in solution as well as the infrared spectrum of (NH4)3VS4 were measured. The Laser technique was used to record the Raman spectra of the crystalline salts Cs2MoS4 (red) and Cs2WS4 (yellow). Using a general valence force field, a modified valence force field and the Urey-Bradley force field, force constants were calculated for VO43−, VS43−, MoS42− and WS42−. The mean amplitudes of vibration at 298 °K were calculated for these ions according to the L matrix method of Morino. For ReO3S− force constants were obtained, assuming a diagonal F matrix. The valence force constants of all ions are discussed with respect to their bond structure.

The infrared spectra of trimethylamine sulfur trioxide in the solid state have been measured in the region from 4000 cm−1 to 80 cm−1. Assignments of the observed spectra are made under C3v symmetry. Calculation of the force constants were carried out by the FG matrix method, assuming the simple valence force field. The force constant of the NS bond is almost equal to that of sulfamic acid. By comparing the force constants with those of the related compounds, it is concluded that trimethylamine sulfur trioxide is a donor-acceptor complex.

Measurements of the effect of hydrostatic pressure on the first order Raman frequencies of Se and Te are reported. All the frequencies of the Raman active modes decrease with pressure. The valence force field model proposed by Nakayama and Odajima is used to explain this behaviour. Es wird iiber Messungen des Einflusses eines hydrostatischen Drucks auf die Raman-frequenzen erster Ordnung von Se und Te berichtet. AIle Frequenzen der Raman-aktiven Moden nehmen mit dem Druck ab. Das von Nakayama und Odajima vorgeschlagene Va-lenzkraftfeldmodell wird ziir Erklarung dieses Verhaltens benutzt.