Eigenstate resolved infrared-infrared double-resonance study of intramolecular vibrational relaxation in benzene: First overtone of the CH stretch

The first eigenstate resolved, near the infrared spectrum of benzene in the region of thr first C-H stretch overtone (6000 cm(-1)) has been obtained with an IR-IR double-resonance molecular beam optothermal spectrometer. Using a hierarchical tree analysis and level spacing statistics, we show that the intramolecular vibrational relaxation occurs nonergodically over at least seven different time scales ranging from 100 fs to 2 ns. (C) 1997 American Institute of Physics.