Thermal energy deuterium beam scattering (TEDS) from Rh(110) surface is reported and compared to helium atom scattering (HAS). Unlike for He, we find quite strong D-2 off-specular diffraction. The D-2 diffraction intensities are fairly isotropic along the [001] and [1 (1) over bar 0], reflecting the presence of a finite dissociation barrier in the potential energy surface (PES) rather than the anisotropic corrugation of the relevant Rh(110) surface electron density. Inelastic D-2 scattering with strong J=0-->2 kinetic-to-rotational energy conversion is also presented and discussed.