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Mercuric oxide is a well‐known and stable solid, but the diatomic molecule Hg−O is very fragile and does not survive detection in the gas phase. However, laser ablation of Hg atoms from a dental amalgam alloy target into argon or neon containing about 0.3 % of 16O2 or of 18O2 during their condensation into a cryogenic matrix at 4 K allows the formation of O atoms which react on annealing to make ozone and new IR absorptions in solid argon at 521.2 cm−1 for Hg‐16O or at 496.4 cm−1 for Hg‐18O with the oxygen isotopic frequency ratio 521.2/496.4=1.0499. Solid neon gives a 529.0 cm−1 absorption with a small 7.8 cm−1 blue shift. CCSD(T) calculations found 594 cm−1 for Hg16O and 562 cm−1 for Hg18O (frequency ratio=1.0569). Such calculations usually produce harmonic frequencies that are slightly higher than the anharmonic (observed) values, which supports their relationship. These observed frequencies have the isotopic shift predicted for Hg−O and are within the range of recent high‐level frequency calculations for the Hg−O molecule. Spectra for the related mercury superoxide and ozonide species are also considered for the first time. [ABSTRACT FROM AUTHOR]

This study examined the impact on school personnel of a psychological report purported to have been authored by a computer-based test interpretation system versus a psychologist. Identical reports were rated in terms of perceived quality, credibility, and interpretation. No effect on subjects' appraisal of the reports based on authorship was found. (47 references) (Author/DB)

The characterization of three MH-C[H.sub.2]C[H.sub.3], M[H.sub.2]-(C[H.sub.2].sub.2) and M[H.sub.3]-CH=C[H.sub.2] complexes are presented. The density functional theory calculations are used for this purpose.

Chemistry of the actinide elements represents a challenging yet vital scientific frontier. Development of actinide chemistry requires fundamental understanding of the relative roles of actinide valence-region orbitals and the nature of their chemical bonding. We report here an experimental and theoretical investigation of the uranium methylidyne molecules [X.sub.3]U[equivalent to]H (X = F, CI, Br), [F.sub.2]CIU[equivalent to]CH, and [F.sub.3]U[equivalent to]CF formed through reactions of laser-ablated uranium atoms and trihalomethanes or carbon tetrafluoride in excess argon. By using matrix infrared spectroscopy and relativistic quantum chemistry calculations, we have shown that these actinide complexes possess relatively strong U[equivalent to]C triple bonds between the U 6d-Sf hybrid orbitals and carbon 2s-2p orbitals. Electron-withdrawing ligands are critical in stabilizing the U(VI) oxidation state and sustaining the formation of uranium multiple bonds. These unique U[equivalent to]C-bearing molecules are examples of the long-sought actinide-alkylidynes. This discovery opens the door to the rational synthesis of triple-bonded actinide-carbon compounds. actinide multiple bond | heavy element | laser ablation | matrix isolation | relativistic quantum chemistry

A series of simple, unique rhenium methlidyne complexes with halogen ligands attached to carbon and rhenium were synthesized from reactions of laser-ablated rhenium atoms with various floro-chloro-, and bromo-fluoromethanes. The complexes are observed to have significant Jahn-Teller distortion which enhances the orbital interactions among carbon, rhenium, and the ligands.

Matrix infrared spectroscopic studies of the MH-[C.sub.2][H.sub.3] and M[H.sub.2]-[C.sub.2][H.sub.2] intermediates in the reaction of ethylene with laser ablated group 5 metal atoms were carried out. It was found that all three metals form dihydro complexes, which may be the final reaction intermediate prior to elimination of hydrogen and the higher oxidation state complex becomes more stable relative to the insertion product going down the group 5 family.

Ultraviolet excitation of uranium atoms which promotes reaction with methane to form the methyl uranium hydride C[H.sub.3]-UH and its [alpha]-H transfer product uranium methylidene dihydride, C[H.sub.2]=U[H.sub.2] is described.

The reactions of laser-ablated group 3 metal atoms with methyl halides are carried out in excess of Ar during condensation and the matrix infrared spectra studied. The results have reconfirmed that the number of valence electrons on the metal is important for agnostic interaction in simple methylidene complexes.

The reactions of laser-ablated group 13 metal atoms with [H.sub.2[O.sub.22] and the products in solid argon are described. Vibrational frequencies of metal hydroxides, MOH, M[(OH).sub.2] and M[(OH).sub.3], where M = Al, Ga, In and Tl, are identified by using isotopic substitution in the infrared spectra and density theory calculations.

The analogous group 4 metal reactions with OCS have resulted in SMCO, OMCS and Mn([[eta].sub.2]-CO)S products. The relatively higher energy of the CO insertion product with respect to the CS insertion product is manifested in lower product yields for the former and the product identifications are verified by isotopic substitution and by density functional vibrational frequency calculations.

The first experimental observation of a titanium alkylidyne complex with an electron-deficient or partially occupied triplet bond from the reactions Ti and C[X.sub.4] (X = F and Cl) molecules are presented. It appears that X lone-pair conjugation contributes to the C-X bond strength and somewhat to the C-Ti bond, and Cl does better than F.

Products in the reactions of H2O2 and H2, O2 mixtures were observed by matrix infrared absorptions and identified through comparisons with vibrational frequencies calculated for these molecules. It was seen that higher oxidation state products are favored for the heavier Mo and W reaction products and lower oxidation state products dominate the Cr reaction chemistry.

The spectroscopic characterization of laser-ablated scandium, yttrium, and lanthanum atoms with CS2 and OCS molecules in an argon matrix are described. Products of the type SMCX and S-M([eta.sup.2]-CX) (X=S or O) are formed on sample deposition and photolysis favored the S-M([eta.sup.2]-CX) complex, while annealing increased the more stable SMCX isomer.

The reactions of group 5 metal atoms and methyl halides have given carbon-metal single, double and triple bonded complexes that are identified from matrix infrared (IR) spectra and vibrational frequencies computed by density functional therapy (DFT). The IR spectra has shown a dramatic increase of the Ta methylidenes upon annealing, indicating that the formation of C[H.sub.3]-TaX and its conversion to C[H.sub.2] triple bond TaHX require essentially no activation energy.

The reactions of Mn, Fe, Co and Ni with [H.sub.2] + [O.sub.2] or [H.sub.2][O.sub.2] are investigated and infrared spectra are used to obtain molecular vibrational information. Mulliken and natural charge distributions have indicated significant electron transfer from metal d orbitals to OH ligands that decreases from Sc to Zn, indicating that the early transition metal hydroxides are more ionic and that the later transition metal hydroxides are more covalent.

Reactions of laser-ablated Y and La atoms with H(sub 2)O(sub 2) gives the M(OH)(sub 2) and M(OH)(sub 3) molecules, the HOMO dehydration product and the cation M(OH)(sub 2)(super +) in solid argon. Density functional calculations show that the dihydroxide molecules and cations are bent in the metal center and the symmetric and antisymmetric O-H stretching modes are observed in the infrared spectra.

Sc(OH)2 and Sc(OH)3 hydroxide molecules, HOScO dehydration product and Sc(OH)2(super +) cation are formed by the laser-ablated Sc atoms reaction with H2O2. Both symmetric and antisymmetric O-H stretching modes are observed for Sc(OH)2 since Sc(OH)2 is bent at the metal center.

Infrared spectra of the products of Group 4 metal atom reactions with H(sub 2)O(sub 2) and with H(sub 2) + O(sub 2) mixtures and electronic structure calculations of metal hydroxide molecules are presented. Results show that titanium atoms react to give zirconium dihydroxide and tetrahydroxide molecules but Ti-(OH)(sub 4) has the S(sub 4) structure with bent Ti-O-H bonds, and Ti-(OH)(sub 2) appears to be nearly linear.

Reaction of coinage metal atoms with H2O2 and with H2 + O2 mixture are investigated, and the major metal dihydroxide products are identified by matrix infrared spectroscopy. Laser-ablated Cu, Ag, and Au atoms react with H2O2molecules during condensation in excess argon to give four new IR absorptions in each system, O-H stretch, M-O-H bend, O-M-O stretch, and M-O-H deformation, which are due to coinage metal M(OH)2 dihydroxide molecules.

Reinvestigation of the vibrational and electronic spectra of the Cu atoms with NO during condensation in solid argon, and binary argon/neon mixtures is carried out. The molecule is bent in all electronic states with Cu-N-O bond angles varying slightly around 130(plusmn)10 degree, but the Cu-N bond force constants are substantially different, denoting larger differences in bond lengths.

Infrared absorptions for the matrix-isolated lead and tin hydroxides M(OH), M(OH)2, and M(OH)4 (M = Pb, Sn) are observed in laser-ablated metal atom reactions with H2O2 during condensation in excess argon. The minimum energy structure found for M(OH)2 has Cs symmetry and a weak intramolecular hydrogen bond.

Laser-ablated Mo atoms react with H2 upon condensation in excess argon, neon, and hydrogen. The molybdenum hydrides MoH, MoH2, MoH4, and MoH6 are identified by isotopic substitution and by comparison with vibrational frequencies calculated by density functional theory.

Laser-ablated Hf atoms react with H2O2 and with H2 + O2 mixtures in solid argon to form the Hf(OH)(sub 2) and Hf(OH)(sub 4) molecules, which are identified from matrix infrared spectra through mixed isotopic substitution and calculation of isotopic frequencies. This study provides the first evidence for a metal tetrahydroxide molecule and indicates that the metal atom reaction with H2O2 in excess argon can be used to form pure metal tetrahydroxide molecules, which are not stable in the solid state.

Hydrogen-bonded complexes of pentachlorocyclopropane with the bases acetonitrile, ammonia, monomethyl-amine, and dimethylamine is isolated and characterized in argon matrices at 16 K. Coordination of the proton of pentachlorocyclopropane (Pccp) to the electron donor (N) of the base is evidenced by red shifts of the CH stretching mode.

The reaction of zinc and cadmium atoms (Zn and Cd) with O2 + H2 in solid argon and neon is reported. The results revealed that laser-ablated zinc and cadmium atoms were deposited with H2 and O2 in excess argon or neon and with O2 in pure hydrogen or deutrium during deposition at 8 or 4 K.

One-dimensional BeH2 polymers are developed. DFT computations confirm that BeH2 polymers are one-dimensional structures based on the observation of a range of strong infrared-active parallel Be--H--Be bridge-bond stretching modes.

Reaction of laser-ablated Zr with CH4 in excess neon during condensation at 5 K forms CH2=ZrH2, the simplest carbene hydride complex is identified by infrared absorptions at 1581.0, 1546.2, 757.0, and 634.5 cm(super -1). Identification of the agostic CH2=ZrH2 methylidene complex is confirmed by an excellent match of calculated and observed isotopic frequencies particularly for the four unique CHD=ZrHD isotopic modifications.

Mercury(II) hydroxide molecules are prepared upon mercury arc lamp irradiation of Hg, H2, and O2 mixtures in solid neon and argon. The strongest three infrared absorptions are identified through isotopic substitution and comparison to frequencies from density-functional theory.