Dynamical processes in ultralong-range Rydberg molecules

超长程里德堡分子(ULRM)代表了一种具有新的化学结合机制的奇异分子物种。它们在2000年由Greene、Sadeghpour和Dickinson从理论上预测，并于2008年由Pfauet等人利用光缔合光谱首次实验发现。从那时起，超大规模物理已成为一个独立的研究领域，与量子光学、量子多体物理和超冷原子物理密切相关。ULRM由Rydberg和基态原子的不同束缚态混合物组成，表现出巨大的键长和偶极矩，并继承了对外场的敏感性。虽然对双原子和多原子ULRM结构的研究已经证明了非常丰富的现象学和通过场设计束缚分子量子态的可能性，但对量子动力学过程，或者换句话说，里德堡ULRM化学，人们知之甚少。这项提议旨在通过对ULRM发生的基本弹性和非弹性过程制定一种系统的办法来缩小这一差距。它将为这些新分子物种及其里德堡化学反应动力学的表征提供一个重大的飞跃。具体地说，我们将探索我们通过大量的ULRM电子结构计算得到的单个和多个绝热势能面上的波包动力学。将采用泵浦技术并进行仿真，以制备和探测初始和最终时间波包。在单个表面上，量子动力学是绝热的电子性质，我们感兴趣的是可能对原始振动波包进行色散、离域和碎裂的多重干扰和散射事件。在几个局部非坐标空间相互作用的势能面的情况下，我们将探索通过避开交叉或圆锥交叉的超快无辐射电子过程的可能性。包括里德堡电子的自旋和基态原子的电子和核自旋的自旋相互作用效应，以及里德堡电子的自旋轨道相互作用效应和与基态原子的相互作用。我们将研究各种不同的弹性和非弹性里德堡化学过程，包括自旋变化碰撞、缔合电离和重里德堡态的形成，以及特别是复合和解离过程。外场将被用来控制分子的几何形状，并控制相应的动力学。所采用的波包传播方法将基于位置空间的多维网格，通过离散变量表示和多组态时间相关的Hartree方法来计算分子的多模振动动力学。

Ultralong-range Rydberg molecules (ULRM) represent an exoticmolecular species with a novel chemical binding mechanism. Theyhave been predicted theoretically in 2000 by Greene, Sadeghpourand Dickinson and were firstly found experimentally in 2008 by Pfauet al employing photoassociation spectroscopy. Since then ULRMhave become an independent research area closely interacting withquantum optics, quantum many-body physics and ultracold atomicphysics. Consisting of a disparate bound state mixture of Rydbergand ground state atoms ULRM exhibit huge bond lengths and dipolemoments and inherit the sensitivity to external fields. Whileinvestigations on the structure of diatomic and polyatomic ULRM havebeen demonstrating the enormously rich phenomenology and thepossibility to design bound molecular quantum states via fields, verylittle is known about quantum dynamical processes, or, in other words,Rydberg ULRM chemistry. This proposal aims at closing this gap bydeveloping a systematic approach to the underlying elastic andinelastic processes taking place for ULRM. It will, as such, provide amajor leap forward with respect to the characterization of these novelmolecular species and their Rydberg chemical reaction dynamics.Specifically we will explore the wave packet dynamics on single andmultiple adiabatic potential energy surfaces which we obtain fromextensive electronic structure calculations of ULRM. Pump-probetechniques will be employed and emulated to prepare and probe theinitial and final time wave packet. On a single surface the quantumdynamics is adiabatic electronic character and we are interested inthe multiple interference and scattering events possibly dispersing,delocalizing and fragmenting the original vibrational wave packet. Inthe case of several potential energy surfaces which interact locally incoordinate space we will probe the possibility of ultrafast nonradiativedecay processes through either avoided crossings or conicalintersections. Spin interaction effects due to the spin of the Rydbergelectron and the electronic and nuclear spin of the ground stateatoms, as well as spin-orbit interaction effects for both the Rydberg electron and the interaction with the ground state atoms shall beincluded. A variety of different elastic and inelastic Rydberg chemicalprocesses will be investigated, including spin changing collisions,associative ionization and heavy Rydberg state formation as well as inparticular recombination and dissociation processes. External fieldswill be used to control the geometry of the molecules and to steer thecorresponding dynamics. The employed wave packet Propagation methods will be based on multi-dimensional grids in position spacevia discrete variable representations and the Multi-ConfigurationTime-Dependent Hartree approach for multi-mode vibrationaldynamics of molecules.