Vibrational analysis of the S2→S1 fluorescence of azulene in a naphthalene mixed crystal at 4.2 K

Publisher Website
Google Scholar
Abstract
The S2→S1 fluorescence of azulene in a naphthalene mixed crystal has been measured from 740 to 1000 nm at 4.2 K. Of the 25 in‐plane fundamentals (exclusive of C–H stretches) of the S1 state, 20 are readily identifiable in emission. A number of other bands are present in the spectrum and these are tentatively identified as S1 out‐of‐plane vibrations induced by vibronic coupling to σπ* and/or πσ* excited electronic states. An emission previously assigned as T1→S0 phosphorescence is shown to be a combination band of S2→S1 fluorescence. The branching ratio of S2 →S0 fluorescence to S2→S1 fluorescence is approximately 7500 for xenon arc lamp excitation; this is an order of magnitude larger than the value reported for short pulse laser excitation. A summary of photophysical parameters for the low‐lying electronic states of azulene, based on the most recent and reliable experimental data, is also presented.

This publication has 24 references indexed in Scilit: