Evidence that irreversible intramolecular vibrational energy redistribution is slow for ring modes up to 8200 cm−1 in S0 benzene

The Impact of a Solvent and a Methyl Rotor on Timescales of Intramolecular Vibrational Energy Redistribution in Aromatic Molecules

“…In the first step (≈100−200 fs), the initial excitation is rapidly redistributed among a first tier of states that is observable in the spectrum observed by Page and co-workers . Then, in a second, slower step (≥10−20 ps), further redistribution occurs into a larger bath of available states being responsible for the line widths and the time scales observed by Nicholson and Lawrance and others . In fact, in our direct time domain experiments, we observe an ultrafast time scale and a slower one with an overall effective time constant of = 50 ± 7 ps, which is somewhat larger than reported from studies in the frequency domain .…”

“…In fact, in our direct time domain experiments, we observe an ultrafast time scale and a slower one with an overall effective time constant of = 50 ± 7 ps, which is somewhat larger than reported from studies in the frequency domain . It should be noted, however, that in the present case may be an average of more than one time constant, and that the data in refs and are likely only sensitive to the intermediate time scales or provide lower bounds for . Also the temperature in both types of experiments is somewhat different.…”