## Abstract

Using a positive column of helium-neon glow discharge plasma at several temperatures between 77 and 294 K, the disalignment rates of excited neon atoms in the 2p_{5} and 2p_{10} (in Paschen notation) levels are measured by a polarization-resolved laser-induced fluorescence technique. For the 2p_{10} case, the disalignment rate due to radiation reabsorption is evaluated from the optical thickness of the plasma measured by a self-absorption method, and then is subtracted from the disalignment rate measured. From the slope of the obtained disalignment rate plotted against the helium atom density we determine the rate coefficients due to helium atom collisions. These rate coefficients are compared with the results of quantum multi-channel close-coupling calculations using the modified long-range potentials proposed by Bahrim and Khadilkar (2009 Phys. Rev. A 79 042715) from the original potentials of Hennecart and Masnou-Seeuws (1985 J. Phys. B: At. Mol. Phys. 18 657). Our present experiment agrees excellently with the theory for the 2p_{5} level at any temperatures between 77 and 294 K, and for the 2p_{10} state only at 294 K. Below 294 K, the experimental rate coefficients for the 2p_{10} state show a more rapid decrease with the decrease in temperature than the theory predicts.

Original language | English |
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Article number | 075206 |

Journal | Journal of Physics B: Atomic, Molecular and Optical Physics |

Volume | 44 |

Issue number | 7 |

DOIs | |

Publication status | Published - 2011 Apr 14 |

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