Multiphoton absorption of OsO4 under two-CO2-laser pulse excitation.

Measurements of multiphoton absorption from the second nonresonant laser beam under two-frequency infrared-laser excitation of OsO4 are reported. Dissociation energy, the fraction of molecules excited by the first resonant laser pulse, and the excitation level have been estimated on the basis of these measurements. The kinetics of highly vibrationally excited molecules is discussed.