Vibrational Spectra of Xanthione and Xanthone

✍ Scribed by H.K. Sinha; L. Chantranupong; R.P. Steer

• Book ID: 102972922
• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 524 KB
• Volume: 169
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1995.1025

✦ Synopsis

The fundamental vibrational frequencies of xanthione (XT) and xanthone (XN), two structurally similar heteroaromatic molecules. have been obtained experimentally using FTIR and Raman spectroscopy. Ab initio RHF/STO-3G** and RHF/CEP-31G and semiempirical RHF/ AMI and RHF/PM3 molecular orbital calculations have been performed to obtain the vibrational frequencies of these molecules from their force fields. A comparison of the experimental and calculated frequencies reveals that all four theoretical methods overestimate the vibrational frequencies and that the rms deviations increase in the order CEP-31G (<) STO-3G** (<) PM3 (<) AM1. The frequencies obtained by the effective core potential, CEP-31G, method are in excellent agreement with experiment when the calculated frequencies are scaled uniformly by a factor of 0.8953. C: 1995 Academic Press, Inc.