CHARGE TRANSFER IN VERY SLOW H+ + D(1s) HALF COLLISIONS

E. Wells*, I. Ben-Itzhak*, K.D. Carnes*, and B.D. Esry#

*J. R. Macdonald Laboratory, Physics Department, Kansas State
University, Manhattan, KS 66506-2604 USA
#ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS
14, Cambridge, MA 02138 USA

When a HD molecule is ionized quickly, about 1% of the HD+(1s?) is in
the vibrational continuum, and the molecule dissociates with less than 1
eV of kinetic energy.  During the dissociation, the electron initially
centered on the deuteron can make a transition to the proton as the 2p?
and 1s? potential energy curves become close to each other.  We are
using this process to study H+ + D(1s) half collisions down to a few meV
collision energy. This is accomplished by measuring the energy of each
dissociating fragment with a COLTRIMS-style apparatus.