Collisional Energy Transfer from Vibrationally Excited Polyatomic Molecules

Abstract

Abstract Intensities and decay rates of delayed fluorescence initiated by CO2 laser excitation of the triplet-state molecules are used to probe collisional relaxation of vibrationally excited polyatomic molecules. Collisional efficiencies for large polyatomic molecules are found not to exceed the value of 10−2-10−3 even in most favourable case of vibrational energy exchange in collisions between parent molecules. At intermediate levels of excitation (1500—12000 cm−1) the average energies <ΔE> transferred per collision with polyatomic molecules increase as <Evib>rn, where m≥2, and decrease with increasing numbers of atoms in the excited molecules.