The low-lying electronic states of YO2− and YO2: A computational study

Abstract

• The vertical excitation spectra of YO 2 – and YO 2 were calculated. • Several bound anionic states of YO 2 – were found. • Electron detachment energies to low-lying doublet states of YO 2 were obtained. The low-lying electronic states of YO 2 − and YO 2 were studied using the SAC-CI theory. The vertical excitation spectra of YO 2 − and YO 2 were calculated. For YO 2 − , the X 1 A 1 state, five valence-bound singlet–triplet pair states (2 1 A 1 /1 3 A 1 , 1 1 A 2 /1 3 A 2 , 1 1 B 1 /1 3 B 1 , 1 1 B 2 /1 3 B 2 , and 2 1 B 2 /2 3 B 2 ), and one dipole-bound singlet–triplet pair states ( 1 B 2 (DB)/ 3 B 2 (DB)) were investigated. For YO 2 , the X 2 B 2 , 1 2 A 1 /2 2 A', 2 2 A 1 , 1 2 A 2 , 1 2 B 1 /1 2 A“, and 2 2 B 2 states were studied. The geometries of these anionic and neutral states were optimized. The adiabatic electron detachment energies from the anionic states to the neutral states can be obtained from these computed results. The vertical electron detachment energies from the X 1 A 1 state of YO 2 − to the low-lying doublet states of YO 2 were calculated and compared with previous experimental photoelectron spectra. Density functional theories (B3LYP, BPW91, and BP86) were also employed to compute the low-lying electronic states of YO 2 – and YO 2 for comparison.