Associative ionization in collisions of metastable helium with H and D

摘要

The exothermic reactions He*plus;Hrarr;HeHplus;plus;eand He*plus;Drarr;HeDplus;plus;ehave been studied by merginghyphen;beams techniques over a range of interaction energyWfrom 0.05ndash;10 eV. The He* represents a composite of He(21S) and He(23S). Data were obtained by observing currents due to the product ions. For each process the relative effective cross sectionQR(i.e., for the composite He*) as a function ofWis the same within experimental error and monotonically decreases with increasingW. TheQRare in excellent agreement with theoretical predictions by Miller, Slocomb, and Schaefer for the reaction He(23S)plus;Hrarr;HeHplus;plus;e. Absolute cross sections have also been extracted from the merginghyphen;beams data. These are in fair agreement with calculated values but lower than some recent crossedhyphen;beam results.