Compacted electrodes made by pressing alpha-copper phthalocyanine (alpha-CuPc) and silver metal powder provide an effective method to measure resonance Raman scattering from alpha-CuPc. We report first and very weak second overtone and combination bands of alpha-CuPc. They are based on progressions in nu(3), nu(4), nu(7) and nu(15) modes. Three of these are A1g vibrations of alpha-CuPc, indicating a much stronger symmetric contribution to overtone scattering than is the case in porphyrins. Overtone profiles at 0 V vs. SCE arise mainly from scattering from 0 to 1 vibronic overtone states with evidence of higher state contributions in some cases. This is in contrast to the more varied profiles of fundamental modes and is as expected from theory. The results support the view that Raman scattering from alpha-CuPc involves a Jahn-Teller distorted excited state and is due to A as well as B term enhancement.
|Number of pages||4|
|Journal||Journal of the Chemical Society, Faraday Transactions|
|Publication status||Published - 7 Feb 1992|
- alpha-copper phthalocyanine
- overtone profiles
- excitation profiles