A sophisticated spin-vibronic model was developed to study electronic and nuclear dynamics in twofold degenerate electron systems. Eigenenergies and eigenfunctions of a model Hamiltonian are calculated in a basis set of products of electronic, electron spin, and vibrational functions. The 2E ground electronic state of the CH3O pyramidal (C3v) system has been studied with the simultaneous treatment of spin-orbit coupling, all linear and quadratic Jahn-Teller interactions including multimode coup...

Low-lying bound and dissociative states of the methoxy radical have been studied at C3v conformations using accurate ab initio quantum chemical techniques. A double-zeta quality basis set augmented with polarization and diffuse functions has been used throughout. The 2A1 excited state is found to have an equilibrium conformation with RCO=1.614 Å, RCH=1.091 Å, and HCO=102.6°, and the three a1 harmonic frequencies have been calculated (3239, 1308, and 733 cm−1). The followin...

The dynamics of S(3P2,1,0;1D2) production from the 193 nm photodissociation of CH3SCH3 has been studied using 2+1 resonance-enhanced multiphoton ionization techniques. The 193 nm photodissociation cross section for the formation of S from CH3S initially prepared in the photodissociation of CH3SCH3 is estimated to be 1×10−18 cm2. The branching ratio for S(3P)/S(1D) is found to be 0.15/0.85. The fine-structure distribution observed for product S(3P2,1,0) is nearly statistical. Possible...

Molecular interactions in 1,3-dimethylimidazolium-bis(trifluromethanesulfonyl)imide ionic liquids are studied by employing the ab initio Hartree-Fock and density functional methods. Different conformers are simulated with respect to molecular interactions between cation and anion. Manifestation of these molecular interactions in the vibrational spectra is discussed. Direction of frequency shifts of the normal vibrations relative to those in free anion and cations are explained by calculating difference electron density coupled with molecular electron density topography.