ITR: Collaborative Research:[ASE]-[SIM]: Dissociative Recombination of Astrophysically Important Polyatomic Molecules

该项目旨在扩展理论的能力，通过称为解离复合的过程，预测电子碰撞对多原子分子破坏的定量速率。 本研究的目的是对电子与多原子分子离子碰撞时发生的解离复合过程进行详细的量子力学计算。 迄今为止，在几乎所有关于这一过程的研究中，出于计算的需要，理论描述都被迫求助于限制维度的模型。最近的研究表明，在某些情况下，三原子靶分子的全三维振动运动可能是至关重要的。 具体地说，在电子从H3+离子的散射中，振动角动量通过Jahn-Teller相互作用耦合到入射电子，导致复合率比有限维模型预测的高几个数量级。 本提案计划利用最近的理论突破，通过分而治之的计算策略来描述低能电子从多原子分子的散射，包括量子力学的所有自由度。如果这个项目是成功的，从理论上描述的能力，并定性地理解，相互作用的电子多原子系统的机制将被推进。 请注意，这项工作的两个主要分支是：（i）在电子结构理论的水平上，在电子连续体中，有和没有电子共振存在的情况下，从头算量子化学问题的协调研究;和（ii）详细研究了电子和核的耦合运动，作为工具使用（取决于系统）或者当它是适当的时标准共振理论，或振转坐标变换和多通道量子缺陷技术。本项目得到了ITR计划下的物理和化学部门。

The project aims to extend the ability of theory to predict quantitative rates for the destruction of polyatomic molecules by electron collision, through the process called dissociative recombination. The goal of this research is to carry out detailed quantum mechanical calculations of the dissociative recombination process that occurs when an electron collides with a polyatomic molecular ion. In almost all studies of this process to date, theoretical descriptions have been forced to resort to models of restricted dimensionality, out of computational necessity. Very recent studies have demonstrated, that the full 3D vibrational motion of a triatomic target molecule can be crucially important in some cases. Specifically, in the scattering of an electron from an H3+ ion, the vibrational angular momentum couples to an incident electron through the Jahn-Teller interaction, resulting in recombination rates orders of magnitude higher than a limited dimensionality model predicts. The present proposal plans to capitalize on a recent theoretical breakthrough, to describe the scattering of a low energy electron from polyatomic molecules, including all degrees of freedom quantum mechanically through a divide-and-conquer computational strategy. If this project is successful, the ability to theoretically describe, and to qualitatively understand, the mechanisms of interacting electron-polyatomic systems will be advanced. Note that the two main arms of this work are: (i) a concerted study of the ab initio quantum chemistry issues, at the level of electronic structure theory in the electron continuum, both with and without electronic resonances present; and (ii) a detailed investigation of the coupled electron and nuclear motions, using as tools (depending on the system) either standard resonance theory when it is adequate, or rovibrational frame transformation and multichannel quantum defect techniques when the most comprehensive treatment is desired.This project is supported by the Divisions of Physics and Chemistry under the ITR Program.