Charge transfer in slow collisions of Na with H+

Collisions between sodium atoms and protons have been investigated using the molecular expansion method. Cross sections are presented for charge transfer from the sodium 3s and 3p levels to the hydrogen n = 2 level, at collision energies up to 34 eV, to determine rate coefficients for the temperature range 1000-20 000 K. A quantum-mechanical description of the relative motion has been used with reaction coordinates to account for electron translation effects. Our results cast doubt on the absolute cross section measurements made by Kushawaha (1983) in laser excitation experiments.