Vibrational relaxation of biacetyl studied by a visible—infrared double resonance technique

The vibrational relaxation of biacetyl following excitation by a highly intense laser pulse at 10.6 micron is studied. The changes in vibrational population are monitored by visible absorption from the ground electronic state to the excited n-π* state. The results indicate that thermal disequilibrium persists for at least 10^?5 seconds after the laser pulse at pressures in the range of 1–40 torr.The implications of these results for the use of high-power infrared lasers in inducing selective chemical reactions are briefly discussed.