MOLECULAR TREATMENT OF ELECTRON-CAPTURE IN COLLISIONS OF N-4+ IONS WITH H-ATOMS

Partial and total cross sections of electron-capture processes in collision of N4+ ions with H atoms are calculated in the collision energy range from 1 eV/amu to 10 keV/amu. Semiclassical and quantum-mechanical molecular-orbital methods with electron translation factors are employed. Two-electron processes are also considered, but they are found to make small contributions at all collision energies. The dominant electron-capture channels are found to be the N3+(3p) state at energies above 300 eV/amu and the N3+(3d) state at energies lower than 300 eV/amu. Three experiments that observed only total cross sections have been reported for this system. The agreement of the present calculation with these measurements is excellent at all energies. In particular, an oscillation observed in the experiment of Huq, Havener, and Phaneuf [Phys. Rev. A 40, 1811 (1989)] is reproduced by our calculation in the energy range 10-300 eV, and the origin of the oscillation is discussed.