Expressions are presented for the low-coverage adsorption isotherm in either the weakly or fully quantum regime. In the former case, a particularly simple result is obtained if a Morse potential suffices to represent the gas-surface interaction. Additionally, a one-dimensional effective potential is derived which incorporates both quantum and periodic corrugation effects at high temperature.

• Received 10 September 1985

DOI:https://doi.org/10.1103/PhysRevB.33.2803