The authors present mol. dynamics simulations of the absorption spectra of the Hg2 mol. in solid Ne, Ar, and Xe. The simulations were performed using classical mol. dynamics (MD) and a diat.-in-mols. (DIM) treatment of the mixing of the different states of Hg2 induced by the environment. The exptl. relative shifts of the X0g+-D1u transition band are qual. well reproduced. The origin of these shifts is identified as the result of two combined factors: the effect of the host onto the Hg-Hg equil. distances and the different interaction of each matrix with the Hg2 electronic states. [on SciFinder (R)]