Epitaxial Si films were grown on the dihydride-terminated (1 X 1) Si (001) surface by pulsed laser deposition at substrate temperatures between 315 K and 625 K. Critical epitaxial thicknesses, measured by high-resolution cross-sectional transmission electron microscopy, were found to be smaller and to increase less rapidly with substrate temperature than critical epitaxial thicknesses observed for molecular beam epitaxy and sputter deposition on the clean (2 x 1) Si (001) surface. In situ reflection high-energy electron diffraction indicated that the surface reconstruction remained (1 X 1) during growth. Ion probe time-of-flight data indicated that incident Si+ kinetic energies ranged from 10 eV to 135 eV. In conjunction with molecular dynamics simulations, these data suggest that epitaxy on the dihydride surface is enabled through transfer of surface H from surface Si to incident Si or subplantation of incident Si.