Abstract
A modified semiempirical method was used to calculate the effect of a simulated polarizable solvent environment on the energy surfaces of zwitterionic glycine and the glycyl dipeptide. It is shown that the allowance of even a small degree of environmental polarizability significantly alters the conformational energy surfaces of these species relative to a gas phase or in vacuo environment. The con-sequences for empirical calculations employing in vacuo derived short-range potentials is explored. Calculations suggest that polarization of the solute may be important and that potentials based on in vacuo calculations may not be generally portable to higher dielectric environments.