Debye–Waller effects in helium diffraction from Ni(115)

Abstract

Debye–Waller effects in helium diffraction from Ni(115) have been analyzed in order to assess corrections required to determine surface corrugation functions from data taken at nonzero temperatures. It can be concluded that effective corrections can be made for all diffraction peaks by measuring the intensity as a function of temperature for the specular peak. Nonlinearities in Debye–Waller plots at high temperatures can be attributed to anharmonic effects but measurements must be carried out at Bragg angles of the three-dimensional lattice to avoid spurious nonlinearities due to the formation of kinks and steps. It can be further concluded that surface corrugation functions can be accurately determined without Debye–Waller corrections in general if the surface temperature is below 300 K and the Debye–Waller factor is not appreciably greater than the value for Ni(115).