Vibrational relaxation and lasers based on intramolecular vibrational transitions in liquids and in molecular crystals

Some characteristics of vibrational relaxation in fluids and molecular crystals are examined, with a view toward the use of fluids and molecular crystals as active media for IR lasers employing molecular vibrational transitions. The vibrational kinetics in such media is analyzed, along with the problem of assessing the characteristic times for vibrational-translational and vibrational-vibrational energy transfer. The difficulties associated with the allowance for collective interactions are examined. The characteristic times are used as a basis to analyze the possibility of obtaining population inversion in the media.