Vibrational excitation and quenching of N+2 in collision with He at relative energies below 1 eV

Abstract

A selected ion flow drift tube (SIFDT) has been used to measure the vibrational excitation of N+2 ions in collisions with He from the detected threshold to about 0.8 eV relative collision energy. The vibrational quenching of N+2 by He has been measured over the same energy range. The measured excitation and quenching rate constants are found to satisfy the principle of detailed balance, implying no significant role for rotational excitation in the excitation or quenching processes. The quenching rate constant fits a linear Landau–Teller plot, −ln KqαKE−1/3cm, in spite of the fact that the collisions at all energies studied are well within the low energy adiabatic regime in which the collision time is long compared to h/ΔEv.