  The H + D_2^+(v=0,1 and 2) charge transfer reaction is studied using an
accurate wave packet method, using recently proposed coupled diabatic potential
energy surfaces. The state-to-state cross section is obtained for three
different channels: non-reactive charge transfer, reactive charge transfer, and
exchange reaction. The three processes proceed via the electronic transition
from the first excited to the ground electronic state. The cross section for
the three processes increases with the initial vibrational excitation. The
non-reactive charge transfer process is the dominant channel, whose branching
ratio increases with collision energy, and it compares well with experimental
measurements at collision energies around 0.5 eV. For lower energies the
experimental cross section is considerably higher, suggesting that it
corresponds to higher vibrational excitation of D_2^+(v) reactants. Further
experimental studies of this reaction and isotopic variants are needed, where
conditions are controlled to obtain a better analysis of the vibrational
effects of the D_2^+ reagents.
