liens
Quantum-mechanical transport properties of N+ (3p) and N+ (1D) ions ..
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 77K mentioned in the work of Tanuma group, prompted us to try quantum calculations to minimize this failure. To do this, we have 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 the N⁺(³P) and N⁺(¹D) ions in He atom are then carefully determined with special emphasis on the behavior 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∼10Td
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