Molecular Solvation Phenomena in Nanoscale Superfluids

加州大学伯克利分校的Birgitta Whaley在理论与计算化学项目的支持下，对两类新型量子溶剂化现象进行了微观理论分析，这两类现象是由最近的光谱实验揭示的，理论上仍然无法解释。目的是揭示在光谱观测中潜在的量子结构和动力学所起的作用。第一个要探索的现象是用分子对氢的溶剂化层“包裹”一个分子，然后在超低温下将其嵌入氦团簇中的效果。将分析氢和溶剂化包层中可能存在的纳米超流动性的程度，以及其量子统计量与分子光谱常数之间的关系。其次，将讨论氦溶剂诱导的嵌入分子和配合物的结构修饰和激发，重点关注分子内隧道，异质配合物的结构，以及平面有机分子周围局部溶剂化环境和相关溶剂激发的性质。本研究涉及大规模量子模拟方法的应用，在某些情况下的算法进步，以及使用动态模型将模拟与理论分析相结合。分子束膨胀产生的氦小液滴团正成为一种日益流行的新介质，原子和分子可以嵌入其中，并在实验中进行研究。该簇作为一种新的环境，用于研究分子的超低温特性、化学反应和溶剂化的能量。该项目的结果有望导致对冷量子力学溶剂中化学和物理行为的基本理解的新见解。

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.