Sr. Cook et Ma. Hoffbauer, ABSOLUTE MOMENTUM-TRANSFER IN GAS-SURFACE SCATTERING, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 55(4), 1997, pp. 3828-3831
Two new parameters called the reduced force coefficients are introduce
d that eliminate the singularity problems associated with the momentum
accommodation coefficients and completely describe the macroscopic av
erage momentum transfer to a surface by an incident gas. In addition,
the reduced force coefficients can be used to determine the flux-weigh
ted average velocity and translational energy of molecules scattered f
rom a surface, and can be used to approximate the energy accommodation
coefficient for many gas-surface interactions. The reduced force coef
ficients for molecular beams of H-2 and N-2 incident upon SiO2-coated
Kapton and Z-93-coated aluminum were obtained using a specialized tors
ion balance to measure the magnitudes and directions of the forces exe
rted on the surfaces by the molecular beams.