Alignment relaxation of Ne*(2p$_{i}$[J=1]) atoms due to collisions with He(1s$^{2}$) atoms

Alignment relaxation of atoms induced by collisions offers accurate information regarding the anisotropic atom-atom potentials and has many applications in atomic and plasma physics. Here we report the energy-averaged cross sections for destruction of alignment $\sigma ^{(2)}$ and the rate coefficients for disalignment K$_{DA}$ of Ne$^{\ast }$(2p$^{5}$ 3p; 2p$_{i}$ [J=1]) atoms due to He atom collisions using a many-channels close-coupling method based on a modified model potential for the HeNe$^{\ast }$(2p$^{5}$ 3p) system [1]. Comparison with measurements using laser-induced fluorescence spectroscopy (LIFS) [2] and Hanle signals [3] is reported. The LIFS method measures K$_{DA}$ due to intra-multiplet transitions, while the analysis of Hanle signals gives $\sigma ^{(2)}$, which incorporates both the intra- and inter-multiplet transitions. Good agreement between theory and experiments was found for the 2p$_{2}$, 2p$_{5}$, and 2p$_{7}$ states at 77 K $<$ T $<$ 350 K when a static polarizability for each Ne$^{\ast }$(2p$_{i})$ state is added to the long-range potentials of the HeNe$^{\ast }$(2p$^{5}$ 3p) system given in Ref.[4]. [1] Bahrim C and Khadilkar V 2008 \textit{J. Phys. B }\textbf{41} 035203 [2] Seo M, Shimamura T, Furatani T, Hasuo M, Bahrim C and Fujimoto T 2003 \textit{J. Phys. B }\textbf{36} 1885 [3] Carrington C G and Corney A 1971 \textit{J. Phys. B }\textbf{4} 869 [4] Bahrim C, Kucal H and Masnou-Seeuws F 1997 \textit{Phys. Rev. A} \textbf{56} 1305