Abstract

The rates of the S₁⇝S₀ and the S₂⇝S₀ internal conversions in azulene were both estimated to be almost of three orders of magnitude greather than expected for internal conversion in aromatic hydrocarbons with equivalent energy gaps (see [1] and references therein). According to Hirata and Lim [1] the S₂ ⇝S₀ internal conversion is already competitive with the S₂⇝S₁ internal conversion in radiationless decay of S₂ of azulene. This picture is in accordance with the experimental results of Griesser and Wild [2] who didn’t find a simple correlation between energy gaps of S₂, S₁ and S₀ states and the rate constants of radiationless transitions from S₂ state in azulene and its derivatives. It must be emphasized, however, that up to now all correlations and interpretations of radiationless transitions from S₂ state in azulene were based on two-electronic-state model, which seems to be particularly inadequate in this case. We may expect that besides a direct couplings S₂⇝S₀ and S₂⇝S₁ also coupling between S₁ and S₀ is of importance in the kinetic of deactivation of S₂ state.

© 1984 Optical Society of America