Multiphoton infrared absorption in CF3I molecules cooled in a pulsed jet

An investigation was made of multiphoton absorption of pulsed CO₂ laser radiation by CF₃I molecules cooled in a supersonic jet. Vibrational excitation of CF₃I was investigated as a function of the energy density in the range 0.05–1.0 J/cm² and of the frequency of the exciting radiation. Multiphoton absorption spectra were recorded and the changes in these spectra due to an increase in the energy density were studied. An investigation was made of the role of the intensity (duration) of the exciting pulses in the multiphoton absorption process. The spectral dependences of the energy density corresponding to the dissociation threshold were obtained and the fraction of the molecules interacting with laser radiation was determined.