ENHANCED CHARGE-TRANSFER TO MOLECULAR-IONS BY ELECTRONIC EXCITATION OF THE TARGET

A beam of molecular ions (ArH+, ArD+, or D3+) was neutralized by passage through an excited cesium vapor; two single-mode diode lasers were used to populate the 6 2P3/2 state of the cesium atoms. The charge-transfer cross section could be increased by laser excitation of the Cs target, in some cases by orders of magnitude. This was established by observing the intensity of the luminescence from the neutralized molecules, which was enhanced by a factor of up to 10. The enhancement factors are in qualitative agreement with results of computations that follow the theoretical treatment for atoms introduced by Rapp and Francis [J. Chem. Phys. 37, 2631 (1962)]. This experimental technique is a generally applicable method for any molecular-beam technique that relies on charge transfer. © 1995 The American Physical Society.