Journal of Physical Chemistry A, Vol.113, No.39, 10564-10576, 2009
Performance of Quasi-Degenerate Scaled Opposite Spin Perturbation Corrections to Single Excitation Configuration Interaction for Excited State Structures and Excitation Energies with Application to the Stokes Shift of 9-Methyl-9,10-dihydro-9-silaphenanthrene
The quasi-degenerate scaled opposite spin perturbation correction to single excitation configuration interaction (SOS-CIS(D-0)) is a promising electronic structure method that can describe electronically excited states of sizable molecular systems. In this article, we report an assessment of the performance of SOS-CIS(DD0) for adiabatic electronic transition energies and excited state equilibrium geometries for various small molecules. These tests allow optimization of the empirical scaling parameter in SOS-CIS(DD0), and it is shown that one universal scaling parameter (chosen as 1.4) can satisfactorily reproduce the experimental results for all the tested molecules. The method is then applied to examine the large Stokes shift observed with a dihydrosilaphenanthrene derivative. The main features of the experimental absorption and emission spectra of this molecule are well reproduced by SOS-CIS(D-0).