Absolute balmer line and NH(c 1Π→b 1Σ+, 0-0) vibrational band emission cross sections from NH3 molecules excited by electron impact

Abstract

The absolute Balmer line emission cross sections are determined in the processes of the electron impact dissociative excitation of ammonia. The optical excitation functions measured for these lines were investigated in the energy range 50–500 eV and normalized by the He benchmark procedure. The molecular continuum contribution has been eliminated from the obtained data. After that, the measured data have been corrected with the collection efficiency factor F to compensate the loss of optical signal due to non-thermal energies of the H excited fragments. The results for kinetic energy distribution functions for the ammonia molecules have been used for the F determination. The optical emission cross sections are determined with the accuracy of ± 15%. The cross sections for the NH(c 1Π→b 1Σ+, 0-0) vibrational band have also been determined with an accuracy of ± 25%.