PICOSECOND STIMULATED-EMISSION PUMPING - INTRAMOLECULAR VIBRATIONAL-RELAXATION IN THE EXCITED ELECTRONIC STATE OF PARA-CYCLOHEXYLANILINE

Intramolecular vibrational energy redistribution (IVR) is studied by picosecond time resolved stimulated emission pumping (TRSEP). This technique is used to obtain decays for 3 of the 19 previously studied vibronic levels in p-cyclohexylaniline. These TRSEP decays allow one to quantitatively measure the ratio of fast to slow fluorescence intensities in order to obtain accurate values for the number of coupled states. This data inspired us to take a closer look at the time decays which eventually led to the understanding of why the medium energy levels exhibit temporal behavior with fast initial decays and small damped quantum beats when large undamped quantum beats are expected. This paper demonstrates that the rotational state interactions are the cause for this interesting behavior.