Potential Energy Curves and Lifetimes of Low-Lying Excited Electronic States of CSe Studied by Configuration Interaction Method

In
this work, we performed a high level ab initio study on the
low-lying electronic states of CSe, utilizing MRCI+Q (the internally
contracted multireference configuration interaction, and Davidson’s
correction) method with scalar relativistic and spin–orbit
coupling effects taken into account. The potential energy curves of
18 Λ–S states associated with the lowest dissociation
limit of CSe molecule, as well as those of 50 Ω states generated
from the Λ–S states were computed. The spectroscopic
parameters of bound states were evaluated, which agree well with existing
theoretical and experimental results. With the aid of calculated spin–orbit
matrix elements and the Λ–S compositional variation of
the Ω states, the spin–orbit perturbations of low-lying
states to the A1Π and a3Π states
are analyzed. Finally, the transition dipole moments of A1Π, A′1Σ+, a3Π0+, and a3Π1 to the ground X1Σ+ state as well as the lifetimes of the
four excited states were evaluated.