Raman scattering tensor elements for some ag modes of anthracene

✍ Scribed by A. Bree; R. Zwarich

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 857 KB
• Volume: 18
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.1250180108

✦ Synopsis

The intensities of the Raman lines of anthracene in solution and in the pure crystal at room temperature have been measured using several excitation frequencies (yo) in the pre-resonance region. The data were used to derive molecular scattering elements aa at each uo for a number of a, fundamentals. While the values of a , and a , are constant over the restricted range of excitation used, a, shows an enhancement as uo moves towards resonance with the first absorption system (I). Overlap factors were determined from the fluorescence spectrum of anthracene in a biphenyl matrix, and these values were used to calculate the contribution a,(I) due to scattering off the first excited electronic state. Working beyond the oriented-gas assumption improved the fit between calculated and observed enhancement. There is a measurable background contribution to a, due to scattering off higher excited states and this has an opposite algebraic sign from a,(I) for all a, fundamentals except possibly for the 394 cm-' mode.