FINITE DEBYE-WALLER FACTOR FOR CLASSICAL ATOM-SURFACE SCATTERING

We consider atom-surface scattering at low surface temperature, fixed incident energy, and fixed interaction potential. We examine the limit as the mass m of the incident particle --> infinity, and thus its de Broglie wavelength --> 0. We show that in this "classical" limit, at zero temperature, the Debye-Waller factor, i.e., the probability of strictly elastic scattering (a quantum effect), tends to a finite limit (< 1). We propose scattering of 20-meV Ar atoms from cold Cu(111) as a promising experiment to verify this effect, and estimate the Debye-Waller factor for this system.