Rotational Transitions in the N2+ Ion Induced by Collisions with Helium Atoms in Cold Helium Plasmas. A Quasiclassical Trajectory Study

• Published in: Chemphyschem 2024-01, Vol.25 (1), p.e202300469-n/a
• Main Authors: Paláček, Stanislav, Kalus, René, Gadéa, Florent Xavier, Benhenni, Malika, Leininger, Thierry, Yousfi, Mohammed
• Format: Article
• Language: English
• Subjects: Artificial neural networks; Chemical Sciences; cold plasma; collision dynamics; Collisions; dinitrogen ion; helium; Helium atoms; Helium plasma; Mathematical analysis; Neural networks; or physical chemistry; Potential energy; rotational excitation; Rotational states; Theoretical and
• ISSN: 1439-4235; 1439-7641
• DOI: 10.1002/cphc.202300469

Cross‐sections of state‐to‐state rotational transitions in electronically ground‐state 14 N2+ ${{\rm{N}}_2^ + }$ (X2 Σg+ ${{\Sigma }_{g}^{+}}$ ) ions induced by collisions with 4He atoms have been calculated using a quasiclassical trajectory method and a set of artificial neural networks representing the N2+ ${{\rm{N}}_2^ + }$ /He potential energy surface. The training points for the neural networks have been calculated at a MCSCF (multi‐configuration self‐consistent field)/aug‐cc‐pVQZ level. A broad range of the N2+ ${{\rm{N}}_2^ + }$ /He collision energy has been considered ( Ecoll≤100 ${{E}_{{\rm c}{\rm o}{\rm l}{\rm l}}\le 100}$  eV) and the efficiency of vibrational transitions in the N2+ ${{\rm{N}}_2^ + }$ ion has also been analyzed. It has been found that vibrational transitions are negligible with respect to rotational transitions up to Ecoll≈10 ${{E}_{{\rm c}{\rm o}{\rm l}{\rm l}}\approx 10}$  eV and that above this energy, both rotational and vibrational transitions in N2+ ${{\rm{N}}_2^ + }$ are marginal in the N2+ ${{\rm{N}}_2^ + }$ /He collisions. The effective cross‐sections of rotational transitions in the N2+ (v=0) ion (j→j′) induced by collisions with a He atom plotted against j′–j as calculated for selected N2+ initial rotational states (j) and a specific value of the N2+/He collision energy (Ecoll=0.5 eV).