Inelastic Processes in Nickel–Hydrogen Collisions

Abstract The cross sections and rate coefficients for inelastic processes in low-energy collisions of nickel atoms and positive ions with hydrogen atoms and negative ions are calculated for the collisional energy range 10 −4 –100 eV and for the temperature range 1000–10,000 K. 74 covalent and three ionic states correlated to 11 molecular symmetries are considered. 3380 partial inelastic processes are treated in total. The study of nickel–hydrogen collisions is performed by the quantum model methods within the Born–Oppenheimer formalism. The electronic structure of the collisional quasimolecule is calculated by the semiempirical asymptotic method for each considered molecular symmetry. For nuclear dynamic calculations the simplified method in combination with the Landau–Zener model is used. Nuclear dynamics within each considered symmetry is treated separately, and the total rate coefficients for each inelastic process have been summed over all symmetries. The largest values of the rate coefficients (exceeding 10 −8 cm 3 s −1 ) correspond to the mutual neutralization processes in collisions Ni + (3 d 9 2 D ) + H − (1 s 2 1 S ) (the ground ionic state being the initial state), as well as in Ni + (3 d 8 4 s 4,2 F ) + H − (1 s 2 1 S ) (the first excited and the second excited ionic states being the initial states) collisions. At the temperature of 6000 K, the rate coefficients with large magnitudes have the values from the ranges (1.35−5.87) × 10 −8 cm 3 s −1 and (1.02−6.77) × 10 −8 cm 3 s −1 , respectively. The calculated rate coefficients with large and moderate values are important for non–local thermodynamic equilibrium stellar atmosphere modeling.