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Accurate potential energy curves, dipole moment functions, dissociation energies and spectroscopic constants for three quartet electronic states (X4Σ−, A4Π and B4Σ−) of the CaN molecule are reported with the multireference singles and doubles configuration interaction methodology. Also, are present radiative transition probabilities and lifetimes for the A4Π–X4Σ−, B4Σ−–X4Σ− and B4Σ−–A4Π band systems. The ground state (X4Σ−) has an equilibrium distance equal to 4.410a0 and the dissociation energy is 0.85 eV. The A4Π has a shorter equilibrium distance equal to 4.142a0 and the B4Σ− has a much longer equilibrium distance, equal to 5.426a0. Radiative lifetimes for v′=0 are predicted to be 27 000, 0.256 and 565 μs for the A4Π–X4Σ−, B4Σ−–X4Σ− and B4Σ−–A4Π band systems, respectively. [Copyright &y& Elsevier]

The electronic states correlated to the first dissociation channel, around 25,500 cm −1 , of the AlC and GaC molecules have been investigated by CASSCF/MRCI methodology with aug-cc-pV5Z basis set. Our work focused on the accurate description of the potential energy curves, dissociation energies, transition moment functions, radiative lifetimes, dipole moments and molecular constants. The B 4 Σ − electronic state has been previously detected for AlC molecule and it is probably not detectable in GaC molecule due to the predissociative character which affects all its vibrational levels. The characterization of the GaC low-lying electronic states were carried out for the first time. [ABSTRACT FROM AUTHOR]

Abstract: Thermochemical and kinetics properties of the hydrogen abstraction and addition processes of the reaction were computed using high-level ab initio and DFT approximation methods with aug-cc-pVXZ (X=T,Q) basis set. The CCSD (T)/CBS//BB1K/aug-cc-pVTZ results for classical barrier height are 13.1 and 15.0kcal/mol for the abstraction and addition reactions, respectively. The thermal rate constants were calculated using the dual-level direct dynamics by variational transition state theory with the BB1K potential energy surface and thermochemical properties corrected with the CCSD (T)/CBS//BB1K/aug-cc-pVTZ results. The rate constants calculated show that the variational and tunneling effects play a relevant role only for the abstraction reaction. [Copyright &y& Elsevier]

Abstract: Accurate potential energy curves, dissociation energies and molecular constants for several low-lying singlet and triplet electronic states of MgS were investigated using the CASSCF/MRCI methodology, and the cc-pVQZ basis set. Our results represent an improvement over previous theoretical description for the lowest lying states, characterize some higher excited states not previously investigated, and also confirm the assignment of the B1Σ+ excited state investigated experimentally. Transition probabilities and radiative lifetimes were also predicted using Einstein spontaneous emission coefficients. [Copyright &y& Elsevier]