Vibrational quenching ofN2(ν=1,jrot=j)by3He:Surface and close-coupling calculations at very low energy

Abstract

A quantum-mechanical investigation of the vibrational deactivation of ${}^{14}{\mathrm{N}}_{2}(\ensuremath{\nu}=1,{j}_{\mathrm{rot}}=j)$ in the ultracold collisions with ${}^{3}\mathrm{He}$ atoms is presented. Ab initio potential-energy calculations are carried out at BCCD(T) level and a global three-dimensional potential-energy surface is obtained by fitting ab initio points within the reproducing kernel Hilbert space method. Close coupling scattering calculations are performed at collision energy ranging from ${10}^{\ensuremath{-}6}$ to 2000 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$. It is shown that the potential-energy surface supports a series of shape and Feshbach resonances. Their influence on the behavior of elastic and inelastic cross sections and quenching rate coefficients is discussed. It is demonstrated that, similar to the ${\mathrm{H}\mathrm{e}\ensuremath{-}\mathrm{O}}_{2}$ system, the rate coefficients exhibit three different regimes: Wigner regime at very low temperatures, van der Waals regime at intermediate temperatures due to series of resonances, and the usual rovibration--translation energy transfer regime at high temperatures.