Franck-condon simulations including anharmonicity of the a-x and SVL emission of HSiCl and DSiCl

Abstract

RCCSD(T) and/or CASSCF/MRCI calculations have been carried out on the 1A? and 1A?? states of HSiCl employing basis sets of up to the aug-cc-pV5Z quality. Contributions from core correlation and extrapolation to the complete basis set limit were included in determining the computed equilibrium geometrical parameters and relative electronic energy of these two states of HSiCl.

Franck?Condon factors which include allowance for anharmonicity and Duschinsky rotation between these two states of HSiCl and DSiCl were calculated employing RCCSD(T) and CASSCF/MRCI potential energy functions, and were used to simulate the 1A?? ? 1A? absorption and 1A?? ? 1A? single vibronic level (SVL) emission spectra of HSiCl and DSiCl. Simulated absorption and experimental LIF spectra, and simulated and observed 1A??(0,0,0) ? 1A? SVL emission spectra, of HSiCl and DSiCl are in very good agreement.

However, agreement between simulated and observed 1A??(0,1,0) ? 1A? and 1A??(0,2,1) ? 1A? SVL emission spectra of DSiCl is not as good. Preliminary calculations on low-lying excited states of HSiCl suggest that vibronic interaction between low-lying vibrational levels of the 1A?? state and highly excited vibrational levels of the 3A?? is possible. Such vibronic interaction may change the character of the low-lying vibrational levels of the 1A?? state, which would lead to perturbation in the SVL emission spectra from these vibrational levels.

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Identifiers

ORCID for John M. Dyke: orcid.org/0000-0002-9808-303X

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