The present work describes how the hydrogen adsorption capacity of graphitic materials in the temperature range between 100 and 300 K can be derived from experimental vibrational energy spectra as well as from results of high level ab initio calculations. It has been found that wrong long-range behavior observed by standard ab initio calculations strongly affects the accuracy of the predicted storage capacity. We have proposed an improved semi-empirical algorithm to calculate adsorption properties. The empirical potential described by Mattera and co-workers in combination with an ab initio calculated parameter set gives a proper theoretical description of the graphite-hydrogen interaction. (c) 2005 Elsevier B.V. All rights reserved.