Solute rotational dynamics at water surfaces

COMP 23

Ilan Benjamin, benjamin@chemistry.ucsc.edu, Department of Chemistry, University of California, 1156 High Street, Santa Cruz, CA 95064
The rotational dynamics of solute molecules adsorbed at the water liquid/vapor interface and the interface between water and carbon tetra chloride are studied using molecular dynamics simulations. By varying the dipole moment of the adsorbed molecule and its location, and by comparing the results with those in bulk water, the effects of dielectric and mechanical frictions on reorientation dynamics and on rotational energy relaxation can be elucidated. The results are discussed in relation to recent progress in understanding the structure of water at interfaces. In particular, the rotational behavior can be explained by considering interfacial hydration, surface roughness and surface polarity.