Ab initio investigation of the vibronic spectrum involving the two lowest-lying electronic states of HCCO

Abstract

The results of ab initio calculations of the vibronic spectra involving both lowest-lying states X2A″ and A2A′ of the ketenyl radical HCCO are presented. Potential energy surfaces are computed by means of the coupled cluster method with perturbative triple corrections [CCSD(T)]. A recently developed ab initio approach for the treatment of the Renner-Teller effect in tetra-atomic asymmetric molecules is applied to calculate the vibronic energy levels. © 1999 American Institute of Physics.