Calculations of the energy accommodation coefficient using classical scattering theory

The theory of the energy accommodation coefficient for exchange of energy between a rarefied gas and a clean surface is developed in terms of the differential reflection coefficient for state-to-state scattering of an incoming atomic projectile and a surface. This theory is applied to classical models which have been shown to accurately predict the measured scattered distributions in numerous state-to-state experiments of monoenergetic beams of atoms scattering from clean single crystal surfaces and from clean liquid surfaces. Full three-dimensional calculations are carried out and compared with available experimental data for the accommodation of rare gases at a clean tungsten surface. Good agreement with the experimental measurements is obtained for the heavier mass rare gases where classical theory is expected to be most valid at all measured temperatures.