Rotational relaxation of nitrogen in helium Original Research Article

Rotational level populations of N2 have been measured in free jets of He + N2 mixtures by an electron beam technique. The experimental data are compared with kinetic calculations, based on theoretical state-to-state rate constants, obtained by the IOS method with an M3SV potential energy surface. Reasonable agreement of the data substantiates the IOS method down to low (≈ 10 K) temperatures. Other available calculations of rotational relaxation times are compared with the present experimental data.