Influence of vibrational excitation of molecules on the electron distribution function in N2 in a high-power laser radiation field

Numerical calculations are made of the electron distribution function of molecular nitrogen in a laser radiation field. Calculations are made of the cross sections for electron ionization of vibrationally excited nitrogen molecules. It is shown that collisions between electrons and vibrationally excited molecules weakly influence the characteristic values of the optical intensity corresponding to optical breakdown. Estimates are made which show that small quantities of readily ionized admixtures in the gas may substantially decrease the laser radiation intensity corresponding to optical breakdown.