Disalignment of the Ne$^{\ast }$(2p$_{10}$ [J=1]) atoms induced by Helium atom collisions from 10K to 3000K

Quantum close-coupling many-channel calculations using the new model potential for the interaction between Ne$^{\ast }$(2p$_{i}$ [J=1]) and He atoms proposed in [1] are performed in order to analyze the depolarization of Ne$^{\ast }$(2p$_{i}$ [J=1]) atoms in a gaseous mixture at thermal equilibrium. For temperatures above 77 K we successfully explain measurements of disalignment done with a laser-induced fluorescence spectroscopy method and destruction of alignment using a technique based on the Hanle effect for all four 2p$_{i}$ [J=1] states of the 2p$^{5}$3p configuration of neon [1, 2]. Our interpretation of the experimental data is based on the anisotropy between collisional channels which asymptotically converge toward the same 2p$_{i}$ [J=1] state [2]. Below 77 K our disalignment rate coefficients for the Ne$^{\ast }$(2p$_{10}$ [J=1]) atoms are much larger than the experimental data [3] after the radiation re-absorption is subtracted from the disalignment rates. The calculations indicate that for the 2p$_{10}$ state, at low collision energies, the nuclear rotation has a strong influence in the overall long-range interaction, while the experimental data suggests that below 16 meV, the intramultiplet transitions within the (2p$_{i}$ [J=1]) state of neon are completely negligible. The discrepancy between theory and experiment is carefully analyzed. \\[4pt] [1] Bahrim C and Khadilkar V 2009 \textit{Phys Rev A} \textbf{79} 042715. \\[0pt] [2] Khadilkar V and Bahrim C 2010 \textit{J Phys B }\textbf{43}235209. \\[0pt] [3] Matsukuma H, Shikama T, and Hasuo M 2011 \textit{J Phys B }\textbf{44 }075206.