Coupled cluster calculations for three low-lying doublet states of linear C 10−

Abstract

Making use of a large basis set of 270 contracted Gaussian-type orbitals partially restricted coupled-cluster calculations including connected triple substitutions (RCCSD(T)) have been carried out for the ground state X̃ 2Π u and two low-lying excited doublet states ( 2Σ g + and 2Π g) of linear C 10 −. The calculated T e value for the 2Π g state amounts to 10 890 cm −1, in close agreement with the T o value of 10 338 cm −1 obtained by absorption spectroscopy in a neon matrix. The observed peaks at 12 330 and 12 430 cm −1 are assigned to the 2 0 1 and 1 0 1 transitions. For the 2Σ g + state, we predict a T e value of 9 951 cm −1. Besides the adiabatic peak, the 2 0 1 transition shows up strongest in the 2Σ g +←X̃ 2Π u band.