Ab initio MRD-CI calculations are presented for the photodissociation
of the HCO+ ion, which plays an important role in the chemistry in int
erstellar space and in combustion flames. One-dimensional potential en
ergy curves along the C-H bond length coordinate are presented for the
lowest eight electronic singlet states. The calculations show that th
e 1(1) Pi stale is the lowest excited state through which dissociation
is possible and which can be reached by dipole-allowed transitions. T
he photodissociation dynamics on the 1(1) Pi potential and through the
higher-lying 2 and 3(1) Sigma(+) slates are studied in the one-dimens
ional approximation, using a time-independent quantum mechanical treat
ment. The geometry dependence of the electric dipole transition moment
is taken into account.