Calculateda4Sgr;minus;,A2Dgr;,B2Sgr;minus;States of CH

摘要

Ab initioCI calculations have been performed over a wide range of internuclear distances to obtain the potential curves for three lowhyphen;lying excited electronic states,a4Sgr;minus;,A2Dgr;,B2Sgr;minus;, of CH. With the computed potential curves, vibrationhyphen;rotational levels are obtained by numerical integration of the radial Schrouml;dinger equations for the motion of the nuclei. The term values are analyzed to yield the conventional spectroscopic constants. Results, with known experimental values in parentheses, areRelpar;Athinsp;2Dgr;rpar;equals;2.074lpar;2.082rpar;thinsp;a.u.,Relpar;Bthinsp;2Sgr;minus;rpar;equals;2.208lpar;2.200rpar;thinsp;a.u.,Relpar;athinsp;4Sgr;minus;rpar;equals;2.047thinsp;a.u.;De0lpar;Athinsp;2Dgr;rpar;equals;1.89lpar;2.01rpar;thinsp;eV,De0lpar;Bthinsp;2Sgr;minus;rpar;equals;0.17lpar;sim; 0.40rpar;thinsp;eV, andDe0lpar;athinsp;4Sgr;minus;rpar;equals;2.88thinsp;eV. The computed spectroscopic constants are found to be within 4percnt; of known experimental values. A potential maximum of height 1600 cmminus;1occurs in the computed potential curve of theB2Sgr;minus;state. Thea4Sgr;minus;state, not known experimentally, is estimated to lie between 0.52 eV and 0.75 eV above theX2II ground state.