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.