Knowledge of the thermal accommodation coefficient (TAC) at high surface temperatures is critical in many applications, including sizing of aerosolized nanoparticles through time-resolved laser-induced incandescence (TiRe-LII). Unfortunately, an understanding of the fundamental physics that underlies this parameter is elusive. To this end, we carry out a comparative analysis of the hard, soft, and washboard cube model predictions and contrast these with molecular dynamics results on helium scattering from high temperature solid and molten silicon surfaces. This treatment elucidates the key physics underlying trends in the TAC with respect to the gas molecule to surface atom mass ratio and the gas-surface temperature ratio at surface temperatures between 1500 and 3000 K. (C) 2017 Elsevier Ltd. All rights reserved.