An ab initio study of mutual neutralization in Na++H- collisions

First principles calculations of mutual neutralization in Na+ + H- collisions have been performed for collision energies between 0.01 and 100 eV. A ten-state molecular expansion has been employed with a quantal description of the relative motion and a diabatic nb initio calculation for the two active electrons. While results for the total neutralization cross section are generally within 15% of those obtained by Janev and Radulovic (1978), cross sections into the less populated final states differ much more, by in excess of an order of magnitude for the 3p level. At 100 eV satisfactory agreement is obtained with the results of Olson and Kimura (1985). The low-temperature rate coefficient for mutual neutralization is calculated to be 3.0 x 10(-7) (T/300 K)(-1/2) cm(3) s(-1). Cross sections for ion-pair production in Na(3l) + H collisions have also been determined, showing substantial differences from the results of Janev and Radulovic (1978), particularly for production from 3s at low energy. Differences of 5% and 35% from the calculations of Olson and Kimura (1985) for 3s and 3p, respectively, at 100 eV are obtained.