Height-height correlations for self-affine surfaces with finite horizontal cutoffs are generally modeled by exponential forms. Three mathematically acceptable, alternate forms for the height-height correlation function are investigated, to explore their impact on the analysis of diffuse x-ray-reflectivity data. The appropriateness of these functions to actual physical samples is explored through comparison with x-ray-reflectivity and scanning-tunneling-microscopy data recorded on known self-affine surfaces.

• Received 22 January 1993

DOI:https://doi.org/10.1103/PhysRevB.48.2873