Vibrational energies for the X̃1 A1, Ã1 B1, and B̃1 A1 states of SiH2/SiD2 and related transition probabilities based on global potential energy surfaces

Tokue Ikuo

Yamasaki Katsuyoshi

Nanbu Shinkoh

Journal of Chemical Physics

Transition probabilities were evaluated for the X˜ 1A1-A˜ 1B1 and A˜ 1B1-B˜ 1A1 systems of SiH2 and SiD2 to analyze the X˜→A˜→B˜ photoexcitation. The Franck–Condon factors (FCFs) and Einstein's B coefficients were computed by quantum vibrational calculations using the three-dimensional potential energy surfaces (PESs) of the SiH2(X˜ 1A1 ,A˜ 1B1 ,B˜ 1A1) electronic states and the electronic transition moments for the X˜ -A˜, X˜ -B˜, and A˜ -B˜ system. The global PESs were determined by the multireference configuration interaction calculations with the Davidson correction and the interpolant moving least-squares method combined with the Shepard interpolation. The obtained FCFs for the X˜ -A˜ and A˜ -B˜ systems exhibit that the bending mode is strongly enhanced in the excitation since the equilibrium bond angle greatly varies with the three states; the barrier to linearity is evaluated to be 21 900 cm-1 for the X˜ state, 6400 cm-1 for the A˜ state, and 230–240 cm-1 for the B˜ state. The theoretical lifetimes for the pure bending levels of the A˜ and B˜ states were calculated from the fluorescence decay rates for the A˜ -X˜, B˜ -A˜, and B˜ -X˜ emissions.

eng

American Institute of Physics

Copyright (c) 2005 American Institute of Physics.

[ISSN] 0021-9606

[DOI] 10.1063/1.1876112

[NCID] AA00694991

[DOI] http://dx.doi.org/10.1063/1.1876112