Absolute differential and total cross sections for charge transfer of O+ with H-2

Absolute differential cross sections (DCS's) are reported for charge-transf er scattering of 0.5-, 0.85-, 1.5-, 2.8-, and 5.0-keV O+ ions by Hz molecul es at angles between 0.04 degrees and 5.4 degrees in the laboratory frame. Cross sections for O+(S-4) ground state and O+(D-2,P-2) metastable ions are presented. The ground-state differential cross section is much less forwar d peaked than is the metastable differential cross section. Over most of th e range of impact energies studied, the O+(S-4) total cross section is foun d to be approximately six times smaller than that for O+(D-2,(2)p). Based o n the DCS data reported here, a possible explanation for the large discrepa ncies in the published ground-state total cross sections is given. The pres ent data confirm the existence of a minimum in the ground-state total cross section at about 2 keV, which has been observed by some other workers. [S1 050-2947(99)00205-X].