Modeling of the N2+ ion in cold helium plasma: dynamics of N2+/He collisions and cross-sections

Abstract

A detailed dynamical study is presented for N2 +/He collisions running in the electronic ground state of the collision complex. Hybrid, quantum-classical dynamical calculations have been performed considering a broad range of collision energies (Ecoll=0.01-100eV) and various initial rotational-vibrational excitations of the N2 + ion. Both non-reactive and reactive (N2 + collision-induced dissociation) cross-sections have been calculated with the momentum-transfer approximation applied to the former ones. A thorough comparison with pseudo-experimental data obtained from mobility measurements reported in the literature via an inverse-method approach has been performed and the effect of the rotational alignment of the N2 + ion on calculated cross-sections has been assessed and analyzed.

Ab initio approaches for N2+ and N2Beseda1, Paláček2, Gadéa3 et al. 2022Computational and Theoretical Chemistry42100View full textAdd to dashboardCite

“…As for N + 2 an encouraging agreement between specific MCSCF and large MRCI results has been found. Moreover, the adopted MCSCF approach leads to a very good agreement with N + 2 /He mobility measurements if used together with a moderate basis set (AVQZ ) and employed on-the-fly in subsequent dynamical calculations [15] and Monte Carlo modelings [16] of the N + 2 /He complex. It thus seems that the electronic structure effects not properly taken into account in the adopted ab initio approach based on the MCSCF method do not much affect the N + 2 /He collision dynamics,except for very low collision energies [15], about and below 0.01 eV.…”

“…Moreover, the adopted MCSCF approach leads to a very good agreement with N + 2 /He mobility measurements if used together with a moderate basis set (AVQZ ) and employed on-the-fly in subsequent dynamical calculations [15] and Monte Carlo modelings [16] of the N + 2 /He complex. It thus seems that the electronic structure effects not properly taken into account in the adopted ab initio approach based on the MCSCF method do not much affect the N + 2 /He collision dynamics,except for very low collision energies [15], about and below 0.01 eV. For these energies, the contribution of missing dynamical electronic correlation in MCSCF is important and may lead to observable differences between theoretical and experimental esti-mates of N + 2 /He collision cross-sections [15].…”

“…It thus seems that the electronic structure effects not properly taken into account in the adopted ab initio approach based on the MCSCF method do not much affect the N + 2 /He collision dynamics,except for very low collision energies [15], about and below 0.01 eV. For these energies, the contribution of missing dynamical electronic correlation in MCSCF is important and may lead to observable differences between theoretical and experimental esti-mates of N + 2 /He collision cross-sections [15]. However, such very low collision energies are not crucial at typical experimental conditions (T = 300 K) even if weak electric fields are considered [16].…”

“…However, such very low collision energies are not crucial at typical experimental conditions (T = 300 K) even if weak electric fields are considered [16]. To avoid unnecessary lengthening of the present paper, the reader is referred for a full discussion of the subsequent calculations to the cited studies [15,16]. The effect of the correlation energy in low-energy N + 2 /He collisions is thus still not fully resolved.…”

“…As there is no (semi)empirical model available for the N + 2 /He system, ab initio calculations are required. Advanced computational methods will thus be used starting from modeling of N + 2 /He electronic structure and potential energy surfaces using accurate ab initio methods (this paper), followed by dynamical calculations of N + 2 /He collisions and calculations of transport properties of the N + 2 ion in helium buffer gas (prospective studies [15,16]).…”