Résumé

The difficulty to reproduce the measured data by a classic-theoretical calculations of mobility of
nitrogen ions N+ in dilute atom-gas of helium He at low temperatures T = 4.3 and 77 K mentioned
in the work of Tanuma group [H. Tanuma, S. Matoba and K. Ohtsuki, Mobility of Ions in Gases,
presented at the Atomic and Molecular Data Application Forum Seminar Aiming at ‘Matching the
Needs and Seeds of Atomic and Molecular Data’ held in National Institute for Fusion Science 17–18
December 2008. <http://dpsalvia.nifs.ac.jp/amdsoc/h201217/Tanuma_ 081217.pdf>], prompted
us to try quantum calculations to minimise this failure. To do this,wehave carried out the calculations
of the potential-energy curves of the low lying states corresponding to the N+ + He ion-atom system
using the SA-CASSCF with MRCI ab initio methods including the Davidson and BSSE corrections.
The transport coefficients of theN+ 3P

andN+ 1D

ions in He atom are then carefully determined
with special emphasis on the behaviour of the reduced mobility with the ratio E/N of the electric field
and the gas density and try to explain its observed decrease near the value E/N ∼ 10 Td.

Information

Item Type:	Journal
Divisions:	» Laboratoire de Physique de la Matière et du Rayonnement
ePrint ID:	1981
Date Deposited:	2019-11-02
Further Information:	Google Scholar
URI:	https://www.univ-soukahras.dz/fr/publication/article/1981

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