Molecular Solvation Phenomena in Nanoscale Superfluids

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Birgitta Whaley of the University of California, Berkeley, is supported by the Theoretical and Computational Chemistry Program to carry out microscopic theoretical analysis of two classes of novel quantum solvation phenomena that have been revealed by recent spectroscopic experiments, which remain theoretically unexplained. The aim is to uncover the role played by the underlying quantum structure and dynamics in the spectroscopic observables. The first phenomenon to be explored concerns the effect of "wrapping" a molecule with the solvation layer of molecular para-hydrogen and then embedding this in a helium cluster at ultra-low temperatures. The extent of nanosuperfluidity possible in the hydrogen and solvation wrap will be analyzed, along with the relation between the quantum statistics of this and the molecular spectroscopic constants. Secondly, helium solvent-induced modifications of structure and excitations of embedded molecules and complexes will be addressed, focusing on intramolecular tunneling, structures of heterocomplexes, and on the nature of the local solvation environment and associated solvent excitations around planar organic molecules. This research involves application of large-scale quantum simulation methodology, algorithmic advances in some cases, and a combination of simulations with theoretical analysis using dynamical models. Small liquid clusters of helium that are produced in molecular beam expansions are becoming an increasingly popular new medium in which atoms and molecules can be embedded and studied experimentally. The clusters act as novel environments in which to examine ultra-low temperature properties of molecules, chemical reactions, and the energies of solvation. The outcomes of this project are expected to lead to new insights into the fundamental understanding of chemical and physical behavior in cold quantum mechanical solvents.