A theoretical study of selected singlet and triplet states of the CO molecule

摘要

Potential energy curves have been obtained for theXthinsp;1Sgr;+,Bthinsp;1Sgr;+,Cthinsp;1Sgr;+, (4)1Sgr;+,Ithinsp;1Sgr;minus;,Athinsp;1Pgr;, andathinsp;3Pgr; electronic states of CO using selfhyphen;consistenthyphen;field plus configurationhyphen;interaction techniques and a large Slater basis augmented with diffuse functions. The calculated spectroscopic constantsTe,re, ohgr;e, and ohgr;exeare in excellent agreement with those from experiment, especially for the lowhyphen;lying valence states. Calculated dipole moment functions for theXthinsp;1Sgr;+,Athinsp;1Pgr;, andathinsp;3Pgr; states also agree well with those from previous theoretical calculations. In particular, ourathinsp;3Pgr; dipole moment function provides further support that the two previous theoretical calculations are preferable to the dipole moment function measured by Wicke and Klemperer. Calculated electronic transition moments for theAthinsp;1Pgr;ndash;Xthinsp;1Sgr;+(CO fourth positive system),Bthinsp;1Sgr;+ndash;Xthinsp;1Sgr;+,Cthinsp;1Sgr;+ndash;Xthinsp;1Sgr;+and (4)1Sgr;+ndash;Xthinsp;1Sgr;+band systems all vary significantly with internuclear distance. Our theoretical radiative lifetimes for the lowest vibrational level of theAthinsp;1Pgr;,Bthinsp;1Sgr;+, andCthinsp;1Sgr;+states are 6.2ndash;9.9, 11.2, and 2.1 nsec, respectively. These theoretical results are in generally good agreement with the experimental measurements.