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Electronic transitions of Cs[C.sub.2], Cs[C.sub.2.sup.-] and Cs[C.sub.4] in neon matrixes were studied. The electronic spectra reveal strong absorptions in the visible range, Cs[C.sub.4] spectrum is consistent with a [C.sub.4.sup.-] chain slightly perturbed by the Cs atom, Cs[C.sub.2.sup.-] shows a weak electronic transition.

A combination of ab initio electronic structure theory, transition state theory and master equation modeling was used to study the kinetics of the reaction CO H[O.sub.2] -> C[O.sub.2] OH. The results have shown that the overall rate coefficient is independent of pressure up to 500 atm for temperature ranging from 300 to 2500 K.

Vertical excitation energies of the C[F.sub.3]Cl molecule are determined from a response function approach with a coupled cluster (CC) reference function in order to examine the absolute photoabsorption oscillator strengths in the molecular-adapted quantum defect orbital formalism (MQDO). The results for the molecular Rydberg transitions have provided better f-values of the isolated Cl atom than the MQDO results.

The crossed molecular beam technique is used to investigate the reaction between ground state carbon atoms, C([super 3][P.sub.j]), and phosphine, P[H.sub.3]([X.sup.1][A.sub.1]) at different collision energies. The identification of cis/trans-HCPH([X.sup.2]A') molecules under single collision conditions has paved a way for the very first carbon-phosphorus bond in extraterrestrial environments like molecular clouds and circumstellar envelopes and even in the postplume chemistry of the collision of comet Shoemaker-Levy 9 with Jupiter.

The kinetics of the CH2I NO2, CH2BR NO2, and CHBrCl NO2 reactions are investigated at temperatures between 220 and 360 Kelvin using laser photolysis/photoionization mass spectroscopy. The bimolecular rate coefficients of all three reactions are found to be independent of the bath gas (He or N2) and pressure within the experimental range (2-6 Torr), and dependent on temperature.

Reduction features of NO over a potassium-doped C12A7-[O.sup.-] catalyst were studied. The C12A7-[O.sup.-]/K catalyst shows good NO storage/reduction abilities with a good sulfur tolerance and the NO conversion and [N.sub.2] selectivity on the C12A7-[O.sup.-]/K catalyst depends on the sample temperature, percentage of potassium, the reduction agent and the composition in the mixture gases.

Poly(dicarbon monofluoride) {[C.sub.2]F}[.sub.n] was studied by electron paramagnetic resonance (EPR) and solid state nuclear magnetic resonance (NMR). The results showed the presence of [sp.sup.3] hybridized carbon atoms that are exclusively bonded to other carbon atoms and ensure the cohesion between fluorocarbon sheet pairs in accordance with the structural model of {[C.sub.2]F}[.sub.n].

The potential energy surfaces of the two lowest-lying triplet electronic surfaces [sup.3.A'] and [sup.3.A'] for the O[sup.3.P] + [C.sub.2][H.sub.2] reaction were theoretically reinvestigated, using various quantum chemical methods. An efficient reaction pathway on the electronically excited [sup.3.A'] surface resulting in H[sup.2.S] + HCCO[A.sup.2A'] was newly identified and is predicted to play an important role at higher temperatures.

An in situ reduction method is presented to synthesize a novel structured MnO(sub 2)/mesoporous carbon (MnC) composite. The results show that different MnO(sub 2) contents could be introduced into the pores of CMK-3 treated with different concentrations of potassium permanganate aqueous solution, while retaining the ordered mesostructure and larger surface area.

The effects of structural and surface properties of carbon materials on the adsorption of benzothiophene (BT), dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MDBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) are investigated in the presence of 10 wt % of aromatics in liquid alkanes that simulate sulfur compounds in diesel fuels. The high-adsorption capacity and selectivity for methyl DBTs show that certain activated carbons are promising adsorbents for selective adsorption for removing sulfur (SARS) as a new approach to ultra deep desulfurization of diesel fuels.

The nonplanar distortions of 135 polycyclic aromatic hydrocarbons (PAHs) are classified as splitting (S-) and arching (A-) distortions based on HF/6-31G(d) optimized structures. The results are important for understanding of nonplanar distortion of PAHs and fullerens and this method is used to semiquantitatively estimate strain energies of such molecules containing hundreds of carbon atoms.

The nonlocal density functional theory (NLDFT) model is used to calculate the pore size distributions (PSDs) of the carbons, from H2 adsorption isotherms measured at 77 K, and then to predict H2 adsorption on these carbons at 87 and 298 K. The results have demonstrated that the NLDFT model with appropriate parameters is a useful tool for optimizing carbon pore structures and designing adsorption systems for hydrogen storage applications.

High levels of ab initio electronic structure theory were used for calculating the heats of formation of saturated and unsaturated diaminocarbenes. 56.4 kcal/mol was the value of heat of formation for the unsaturated triplet carbene.

A quantum chemical study of the reaction between NH (X(super 3)sigma(super -)) and H(sub 2), H(sub 2)O, and CO(sub 2) is performed. A route from the triplet-state reactants to the singlet state products of lowest energy, which is HNO + CO, involving intersystem crossing is found.

The overall rate coefficients of the reactions of CSe(sub 2), SCSe, and OCSe with O((super 3)P) atom are examined. An excellent match between the decay rate of OCSe with the appearance rate of CO upon O atom reactions is found, which suggest that only a single channel is open while the measured rate coefficient may be used to describe the single reaction, O + OCSe -> CO +SeO.

The reactions of C1 atoms with XCH(sub 2)I (X=H, CH(sub 3), C1, Br, I) were studied using cavity ring-down spectroscopy in 25-125 Torr total pressure of N(sub 2) diluent at 250K. Absorption attributable to the formation of the XCH(sub 2)I-C1 adduct following the reaction of C1 atoms with XCH(sub 2)I (X=H, CH(sub 3), C1, Br, I) was measured as a function of temperature over the range 250-320 K.

Density functional theory calculation was carried out for hydrogen adsorption on the (001), (110), and (100) surfaces of Fe(sub 5)C(sub 2) and found that the most stable hydrogen species is C(sub S)H at 1/3 and 2/3 monolayer (ML) on (001). On the metallic Fe(Sub 5)C(sub 2)(100) surface which lacks surface carbon atoms on the surface monolayer, dissociated hydrogen is found at 1/2 ML, while both dissociated hydrogen and activated H(sub 2) are found at 1 ML.

The study reports on the solution-phase structure of C(sub 60) in nonpolar o-xylene using a positronium (Ps) atom as a fundamental probe, mapping changes in the local electron density of the microenvironment. Transmission electron microscopy images of the aggregated clusters, in corroboration with Ps annihilation characteristics and pyrene fluorescence, revealed the clusters to be hexagonally close packed microcrystals.

Open-chain calcium-doped carbon clusters CaC(sub n), CaC(sub n)(super +), and CaC(sub n)(super -) (n = 1-8) is discussed through the density functional theory at B3LYP/6-311G(d) and B3LYP/6-311 +G-(d) theoretical methods. For the neutral open-chair clusters the ground state is found to be a triplet [(super 3)Pi] for n-odd members and a single [(super 1)Sigma] for the n-even ones.

Effects of the atom model and the atomic charge parameters on the calculated free energy of hydration (FEH) are studied for CH3OH, CH3NH2, CH3CN, and N(CH3)sub3 with the all atom vs the united-atom model for the CH3 group. The all-atom model, in combination with solute charges derived on the basis of the SCIPCM/B3LYP/6-31G* ELPO, predicts too negative hydration free energies for CH3NH2 and CH3CN.

C-Cu orbital interactions between a two-layer Cu10 or three-layer Cu34 cluster model of a Cu(111) surface and an adsorbed single C60 molecule are theoretically analyzed to elucidate the nature of the C60-Cu(111) bonding and orientational configuration of the C60 molecule on a Cu surface. Results reveal that a single C60 molecule must contact a Cu(111) surface preferably by an edge carbon atom located at the center of two six-membered and one five-membered fused rings or by a C-C bond jointing two six-membered rings (6-6 bond).

Electron spin transient nutation (ESTN) measurements performed with phase inverted echo amplitude nutation is reported. The advantage of this method is that all echoes can be detected at the same time, thus minimizing loss of resolution because of relaxation broadening and also minimizes distortions arising from spectrometer deadtime.

Mutiwalled carbon nanotubes are grown on various substrates by thermal chemical vapor deposition using multilayered metal catalysts. The mutiwalled carbon nanotubes towers exhibit a very strong attachment to the silicon substrate.

The Diels-Alder reaction of s-cis-1,3-butadiene on the diamond surface was examined using the ab initio molecular orbital calculations. The calculations showed that the Diels-Alder reaction could be easily caused on the C(001)-(2x1) surface by the dienes containing heteroatoms like nitrogen (N) or sulfur (S).

A study shows the results of ab initio calculations on a series of [MH]n polyhedral cages (M = C, Si, Ge, and Sn; n = 4, 6, 8, 10, 12, 16, 20, and 24). In conclusion, the partitioned ring energies presented are applied to predict the relative stability of other cages.

The compounds 1,9-C60(CF3)2 and 3 isomers of C60(CF3)10, including the structurally characterized derivative 1,3,7,10,14,17,23,28,31,40-C60(CF3)10 (C60(CF3)10-3) is studied. The significant finding is that this radical anion has a half-life in solution at 25 degree centigrade of about 7 min.

Ab initio post-Hartree-Fock and density functional theory calculations were used to study the equilibrium molecular structure of the octateranyl anion, [C.sub.8][H.sup.-] detected in two astronomical environments. The results obtained from the optimized geometry of [C.sub.8][H.sup.-] provide insight into the dynamics of carbon-carbon bond lengths of [C.sub.8][H.sup.-] as one proceeds from the naked carbon atom on one side of the chain to the CH unit on the opposite side of the chain.

Vibronic optical emissions from CS(A[super 1][pi] -> X[super 1][SIGMA.sup.+]) and CS([a.sup.3][pi] ->[X.sup.1][SIGMA.sup+]) are studied from the dissociative recombination of C[S.sub.2.sup.+] and HC[S.sub.2.sup.+] plasmas using optical monochromator. The results show that CS(A[super 1][pi] -> X[super 1][SIGMA.sup.+]) and CS([a.sup.3][pi] ->[X.sup.1][SIGMA.sup.+]) occur due to dissociative recombination and the C[S.sub.2.sup.+] (A[super 1][pi] -> X[super 1][SIGMA.sup.+]) transitions arise from the ion-molecule reactions.

Equation-of-motion and coupled-cluster methods are used characterizing the electronic structure of C[O.sub.3]. The ground-state equilibrium structures and frequencies are strongly affected by vibronic interactions with low-lying excited states and the vibronic interactions are increased by the Jahn-Teller character of the excited states at [D.sub.3h] geometries.

The quantum mechanical calculations at the B3LYP/6-31+G(d,p) level were used to investigate the intrinsic conformational preferences of proline analogues having double bonds between carbon atoms in their rings. It was found that the double bonds affect the ring puckering and the geometric internal parameters even though the backbone conformation was influenced the most.

A study of the reactions of the dicarbon molecules in their electronic ground, ([C.sub.2([X.sup.1][[SIGMA.sub.g].sup.+]]), and first excited state, ([C.sub.2]([a.super.3][Pi.sub.u]) with acetylene, [C.sub.2]H2([X.super.1][[SIGMA.sub.g.sup.+]]) to synthesize the 1,3-butadiynyl radical, ([C.sub.4]H([X.sup.2][SIGMA.sup.+])), plus a hydrogen atom was carried out at six various collision energies ranging from 10.6 to 47.5 kJ[mol.sup. -1) under single collision conditions. It was inferred that in extreme environments like circumstellar envelopes of dying carbons stars and combustion flames, 1, 3-butadiynyl radical can be formed via bimolecular reactions using carbon clusters.

The structures, energetics, spectroscopies, and stabilities of the doublet NC2O radical are explored at density functional theory and ab initio levels. An evaluation of the important thermochemical characteristics for the isomers of the NC2O radical, including the adiabatic ionization potentials, adiabatic electronic affinities as well as their heats of formation are described.

Various levels of calculations are applied to obtain the structures, energies, dipole moments, vibrational spectra, rotational constants, and isomerization of SiC3P species. The global minimum is found to be a linear SiCCCP of the (super 2)pi electronic state.

An analytical molecular potential, which is proposed by Girifalco and some further more modification to it is presented. The results of two similar studies have shown small differences with GirifalcoEs, which is attributed to differences in the accuracy of the numerical integration, hence confirming the accuracy of the present modified study.

A study of the dissociative recombination of C(sub 3)H(sub 7)(super +) with electrons in a heavy-ion storage ring, CRYRING, has been presented. The results of the study indicate that the dissociation channel corresponding to loss of a single hydrogen atom dominates, with a branching ratio of 0.42.

The charge transfer reaction O(sub 2)(super +) + C(sub 9)H(sub 12) -> O(sub 2) + C(sub 9)H(sub 12) was used to prepare highly vibrationally excited n-propylbenzene cations, C(sub 9)H(sub 12). A study was conducted on the subsequent competition between fragmentation of C(sub 9)H(sub 12)(super +) into C(sub 7)H(sub 7)(super +) + C(sub 2)H(sub 5) and stabilization in collisions with N(sub 2) at temperatures in the range 423-603 K and at pressures between 15 and 200 Torr.

An explicit molecular sieving effect of single-wall carbon nanohorn (SWNHs) due to nanowindow is presented. The accessibility of internal nanospaces of the SWNHs through nanowindows to He, Ar, N2, CH4, SF6, and C60 are determined.