Density functional theory calculations of thiophene adsorption oil the different surfaces of MoS2 show, unlike previous theoretical works, that the most probable adsorption mode is eta(1) through the sulfur atom of the molecule on the sulfur edge of the catalyst particles. The adsorption proceeds oil the stable surface, and there is no need to remove a sulfur atom from the surface before the adsorption. The calculated vibrational wavenurnbers of the adsorbed molecules allowed u to confirm previously published experimental spectral assignments. This work demonstrates the importance of an accurate description of the surface taking into account the nature of the surrounding atmosphere. (c) 2006 Elsevier Inc. All rights reserved.