A theoretical study of the electronic spectra of the SiC 2H radical

Abstract

We have performed an ab initio study of the vertical electronic spectra of the lowest-lying doublet and quartet species of the SiC 2H system. The ground state presents two species of comparable energy, namely a linear SiC 2H( 2 Π ) species and a cyclic SiC 2H( 2 A ′ ) form. The lowest quartet species is SiC 2H( 4 Σ − ). We have encountered a rather intense transition in the case of both SiC 2H( 2 Π ) ( 4 2 Π← X 2 Π , 5.6 eV) and SiC 2H( 2 A ′ ) ( 7 2 A ′← X 2 A ′ , 6.3 eV), as well as a number of moderately intense transitions. In the case of SiC 2H( 4 Σ − ), we have found only a moderately intense transition, namely 3 4 Π← X 4 Σ − at 4.9 eV. The lowest-lying excited state of SiC 2H( 2 Π ) is 2 Δ , which is 3.6 eV higher in energy, while it is 2 A ″ in the case of the cyclic species and lies more closely at 1.9 eV. In the case of SiC 2H( 4 Σ − ), the lowest excited quartet state is 1 4 Π , which is 1.5 eV higher in energy.