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Fundamental understanding of the structure and dynamics of the Li+ ion in solution is of utmost importance in different fields of science and technology, especially in the field of ion batteries. In view of this, ab initio molecular dynamics (AIMD) simulations of the LiCl salt in water, methanol and acetonitrile were performed to elucidate structural parameters such as radial distribution function and coordination number, and dynamical properties like diffusion coefficient, limiting ion conductivity and hydrogen bond correlation function. In the present AIMD simulation, one LiCl in water is equivalent to 0.8 M, which is close to the concentration of the lithium salt used in the Li-ion battery. The first sphere of coordination number of the Li+ ion was reaffirmed to be 4. The radial distribution function for different pairs of atoms is seen to be in good agreement with the experimental results. The calculated potential of mean force indicates the stronger interaction of the Li+ ion with methanol over water followed by acetonitrile. The dynamical parameters convey quite high diffusion and limiting ionic conductivity of the Li+ ion in acetonitrile compared to that in water and methanol which has been attributed to the transport of the Li–Cl ion pair in a non-dissociated form in acetonitrile. The AIMD results were found to be in accordance with the experimental findings, i.e. the limiting ion conductivity was found to follow the order acetonitrile > methanol > water. This study shows the importance of atomistic level simulations in evaluating the structural and dynamical parameters and in implementing the results for predicting and synthesizing better next generation solvents for lithium ion batteries (LIBs). [ABSTRACT FROM AUTHOR]

The partitioning of the available energy into the internal states and the translation of OH was evaluated by measuring the rovibronic lines and their doppler profiles. It was found that 75% of the total available energy was channeled into relative fragment translation, suggesting the C-O bond fission has a barrier in the exit channel.

The gas-phase reactions of atomic hydrogen with various fluoromethanes are studied using direct ab initio dynamics calculations. It is shown that the activation energies of these reactions are affected by the symmetry of the reactions rather than the number of fluorine substitutions. Reactions with the same symmetry have similar transition state structure and barrier height. The thermal rate constants obtained are also in good agreement with experimental values.

The dynamics of the formation of OH radical upon 193 nm excitation of pyruvic acid has been investigated by the laser-photolysis laser-induced-fluorescence technique. OH radicals were generated in the ground electronic state, with no vibrational excitation. The estimated rotational temperature is 720±90 K, and the translational energy is 18.7±6.5 kcal mol[SUP-1]. Ab initio calculations on excited electronic states were performed at the configuration interaction with single electronic excitation level with 6-31+G(d,p) basis function. All low-lying electronic excited states (S1-S3 and T1-T6) were characterized and the transitions were identified. A transition state for the C-OH dissociation channel has been obtained from the T1 state with a late exit barrier. A mechanism for the formation of OH radicals involving internal conversion and intersystem crossing from the initially populated S3 state to T1 state and the dissociation from the T1 potential energy surface with the calculated barrier is proposed, which reproduces the observed partitioning of available energy in the fragments according to the hybrid model. [ABSTRACT FROM AUTHOR]

Various spectroscopic methods are used for examining the dihydrogen-bonded complex between phenol and triethylgermanium hydride. The results have confirmed the formation of an O-H...H-Ge dihydrogen-bonded complex between phenol and triethylgermanium hydride.

A theoretical study is presented of the nature of bonding in several weakly bound radical cation complexes from second and third row hydrides. The Becke's half-and-half (BHH) non local exchange and Lee-Yang-Parr (LYP) nonlocal correlations functionals (BHHLYP) have been found to describe the 2c-3e bonded systems within the restricted open shell formalism.

RATIONALE: Sulfur hexafluoride (SF6) being a potential greenhouse gas, coupled with its numerous applications, makes the study of the formation and fragmentation of SF6-based species important. The formation of SF6-based anionic species has been studied using the gas feed-sputtering route and the mechanisms at play during the sputter-ejection of guest molecule-derived particles have also been probed. METHODS: Studies of the formation of SFn - (n = 1-6) anions were conducted from various surfaces (metal and compound) that were subjected to Cs+ ion sputtering in the presence of SF6 gas employing the gas feed-cesium sputter technique. The anions generated were mass analyzed using a double-focusing magnetic sector mass spectrometer. Quantum mechanical computations were performed to study the ground state structure and stability of neutral and negatively charged SFn (n = 1-6) systems applying density functional theory (DFT) and ab initio methods (MP2 and CC). RESULTS: This technique readily generated 32SFn - (n = 1-6) anions for all sizes of 'n' with practicable yields. Mass spectrometric measurements of the yield of sputter-ejected 32SFn - (n = 1-6) anions reveal an oscillatory pattern as a function of 'n', with odd values of 'n' being relatively more abundant. The relative yield of 34SFn - (n = 1-6) anions with respect to size was also measured albeit with low signal intensity. Also observed were F-, S-, F2 -, 33SF5 - and 33SF6 - anionic species. The relevant electron affinity and bond dissociation energy (BDE) values were also computed. CONCLUSIONS: Gas-phase SFn - (n = 1-6) anions can be effectively generated by using the gas spray-cesium sputter technique. Both experimental measurements and calculations indicate the existence of odd-even oscillations in the stability and electronic structure of the SFn (n = 1-6) systems. The highest yield recorded was for the sputter-ejected SF5 - species and this may be attributed to its 'superhalogen' anionic character coupled with the relatively favorable F0 fragmentation pathway of sputtered SF6 -. A signature pertaining to intact SF6 - anion ejection is also observed. [ABSTRACT FROM AUTHOR]

A series of chalcogenoether ligands RE(CH2) nNMe2 ( 1) [E = Se or Te; R = Ph, o-tol ( o-tol = ortho-tolyl), Mes (Mes = 2,4,6-trimethylphenyl); n = 2 or 3] and their palladium complexes [PdX2{RE(CH2) nNMe2}] m [X = Cl ( 2) or OAc ( 3); m = 1, 2] were synthesized. Complexes [PdCl2(RECH2CH2NMe2)] [R/E = Ph/Se ( 2a), Mes/Se ( 2b), Mes/Te ( 2c)] were isolated as monomers. Complexes [PdCl2(RECH2CH2CH2NMe2)] m [R/E = Ph/Se ( 2d), Ph/Te ( 2e), o-tol/Te ( 2f)] exist in one monomeric and two dimeric forms in solution; their ratio depends on E and R as revealed by NMR spectroscopic data. Crystal structures of monomeric 2a, 2b, 3b, 2d, 2f, and dimeric 2e were established. Compounds 2a, 2d, 2e, and 2f were also investigated by means of density functional theory (DFT)-based quantum chemical calculations to understand structural variation. The complexes that contained acetate or chalcogenoether ligands with n = 3 showed higher catalytic activity than other derivatives in Suzuki C-C cross-coupling reactions. [ABSTRACT FROM AUTHOR]

Ab initio dynamics were used to obtain thermal rate constants for inner-hydrogen atom transfer in porphyrin.