Evaluation of Expansion Coefficients from Optimal Fitting Parameters for the Analysis of Spectra of Diatomic Molecules and an Application to LiH

✍ Scribed by Hiromichi Uehara; J.F Ogilvie

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 138 KB
• Volume: 207
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.2001.8333

✦ Synopsis

To evaluate individual expansion coefficients composing fitting parameters of the Born-Oppenheimer corrections to Dunham's coefficients Y i j that have been given analytically with the B and ω formalism, we examined the consistency of analytic expressions for those corrections with Watson's assertion of the experimental inseparability of nonadiabatic corrections Q a,b (r ) for a molecule AB. Derived analytic expressions in terms of optimal fitting parameters for the corrections are essential to evaluate individual expansion coefficients. These expressions also reveal redundancies between empirical correction parameters i j . A method of evaluating nonadiabatic vibrational corrections Q a,b (r ) and adiabatic corrections S a,b (r ) separately consistent with Watson's assertion of inseparability is presented and is applied to an analysis of spectral data of LiH. Functions Q a,b and S a,b for LiH are thus successfully evaluated; S H,Li (r ) values agree well with those predicted simply by wobble-stretch theory. Experimental values for optimal fitting parameters r H 1q and r H 2q are nearly equal to those of r Li 1q and r Li 2q , respectively, in agreement with a theoretical relation r a iq = r b iq .