Computational Studies of the Rotational Structure of Atomic and Molecular Clusters with Weak Interactions

犹他州立大学的David Farrelly在理论和计算化学计划的支持下，使用扩散蒙特卡罗(DCM)方法研究了弱相互作用原子和分子团簇的转动结构。该项目的主要目标是开发新的计算方法，用于研究液氦纳米液滴中杂质分子和团簇杂质的大振幅旋转动力学，如氦纳米液滴隔离光谱。新技术将普遍适用于氦液滴或气相中刚性顶层分子组合的旋转结构。此外，还将继续研究超高分子里德堡态，并将其应用于零电子动能(ZEKE)光谱学。理论化学中的一项重要任务是计算物质在不寻常或极端情况下的性质。正是在这样的条件下，新的和有趣的财产才会浮出水面。超流体液氦的纳米液滴提供了这样的环境来探索插入其中的分子或小的、弱结合的分子簇。这种液滴被称为终极光谱基质，因为它们的温度非常低，对正在研究的掺杂剂分子的影响很弱。这些纳米液滴为了解物质的新性质和基本的溶剂效应提供了重要的机会。

David Farrelly of Utah State University is supported by the Theoretical and Computational Chemistry Program to use diffusion Monte Carlo (DCM) methods to study the rotational structure of atomic and molecular clusters with weak interactions. The major project goal is to develop new computational approaches for examining large amplitude rotational dynamics of impurity molecules and cluster impurities in liquid helium nanodroplets, as in helium nanodroplet isolation spectroscopy. The new techniques will be generally applicable to rotational structure of assemblages of rigid top molecules in helium droplets or in the gas phase. Also, investigations will continue into ultrahigh molecular Rydberg states, with applications to zero electron-kinetic energy (ZEKE) spectroscopy. An important task in theoretical chemistry is the computation of properties of matter in unusual or extreme situations. It is often under such conditions that new and interesting properties come to light. Nanodroplets of superfluid liquid helium provide such an environment to explore molecules or small, weakly bound clusters of molecules inserted into them. Such droplets have been called the ultimate spectroscopic matrix, because of their very low temperatures and the weak influence they exert on the dopant molecules under study. These nanodroplets present significant opportunities to understand new properties of matter and fundamental solvent effects.