  Radiative decay processes at cold and ultra cold temperatures for Sulfur
atoms colliding with protons are investigated. The MOLPRO quantum chemistry
suite of codes was used to obtain accurate potential energies and transition
dipole moments, as a function of internuclear distance, between low-lying
states of the SH$^{+}$ molecular cation. A multi-reference
configuration-interaction (MRCI) approximation together with the Davidson
correction is used to determine the potential energy curves and transition
dipole moments, between the states of interest, where the molecular orbitals
(MO's) are obtained from state-averaged multi configuration-self-consistent
field (MCSCF) calculations. The collision problem is solved approximately using
an optical potential method to obtain radiative loss, and a fully two-channel
quantum approach for radiative charge transfer. Cross sections and rate
coefficients are determined for the first time for temperatures ranging from 10
$\mu$ K up to 10,000 K. Results are obtained for all isotopes of Sulfur,
colliding with H$^{+}$ and D$^{+}$ ions and comparison is made to a number of
other collision systems.
