Influence of a buffer gas on multiphoton dissociation of molecules in the radiation field of a pulsed CO2 laser

An experimental study was made of the influence of a buffer gas (argon) on the yield and isotopic selectivity of the dissociation of the CF₂Cl₂, CF₂HCl, and CF₃Cl molecules by pulsed CO₂ laser radiation. The dependences obtained were analyzed taking into account the processes of rotational and VT relaxation, and collisional line broadening. A correlation was discovered between the characteristic features of the influence of the buffer gas on the dissociation of the molecules and the existence of lf molecular vibrations in them. A suggestion was put forward of the existence of a broad component in the spectrum of the lines due to transitions in the polyatomic molecules. It was concluded that collisional line broadening is the principal factor responsible for increasing the dissociation yield of the molecules when a buffer gas is added.