ON THE RELATION BETWEEN FREQUENCY SHIFTS AND ELECTRON DENSITY SHIFTS. Kersti Hermansson, Dept. of Chemistry, Uppsala University, Box 531, S-75121 Uppsala, Sweden

The frequency shift of the intramolecular stretching vibration of a diatomic molecule is a sensitive probe of the strength and nature of intermolecular bonding. For some diatomics, the intramolecular bond gets stronger, for others weaker, when the molecule is bound by intermolecular forces.

The poster explains how electron density maps of the vibrating free molecule will tell us if a frequency upshift or a downshift will occur when the molecule is bound in a crystal.