Theoretical Study of Dynamical Processes in Highly Excited Molecules up to Double Ionization

我对高激发态的动力学过程进行了理论研究，这些高激发态的能量接近并高于第一电离势。主要研究的过程是解离复合（DR）和解离激发（DE）。其机制与其他过程共同，如通过电子碰撞的旋转和振动激发。在这些过程中，电子和核运动之间存在强的量子力学和高密度耦合。本文提出了一些理论方法来描述这些复杂过程，并通过数值计算阐明了这些过程的机理和现有方法的有效性。所研究的分子体系是H_2和HeH及其同位素，这是两个典型的受不同机制控制的体系，在DR中，如果HD^+ + e，其机制随碰撞能的变化而变化。在较低能量下，我们研究了包括转动运动在内的过程，并精确地估计了非绝热电子共振散射的影响。这是第一个代表实验结构的结果。在高能量下，通过将离散化的离解基函数引入到通常的多通道量子亏损理论中，计算了DR和DE截面。除了获得原子数据外，本文还揭示了DR和DE的共同机制。本文的研究揭示了HeH^+的DR中没有解离共振态的大截面的原因。通过引入闭合解离通道的概念，可以描述解离态之间的非绝热耦合。本计算再现实验光谱和同位素依赖性的第一次。

I have done theoretical studies on the dynamic processes relevant to the highly excited electronic states, of which energies are near and higher than the 1st ionization potential. The processes mainly studied are dissociative recombination (DR) and dissociative excitation (DE). of which mechanism is common to the other processes as rotational and vibrational excitation by electron impact. There is strong, quantum mechanical, and high density coupling between electronic and nuclear motion in those processes. I developed some theoretical methods to represent those complex processes, and made clear the mechanism of those processes and availability of the present methods by numerical calculation. The studied molecular systems are H_2 and HeH and those isotopes, which are typical two systems controlled by quite different mechanisms.In the DR if HD^+ + e, its mechanism changes with collision energy. At the lower energy, I investigated the process including the rotational motion and estimating precisely the effect of nonadiabatic electronic resonance scattering. This result the first to represent the experimental structures. At the higher energy, I calculated the DR and DE cross sections by introducing the discretized dissociative basis functions to the usual multichannel quantum defect theory. Besides obtaining the atomic data, I show the common mechanism between the DR and DE.The present study shows the reason of large cross section in the DR of HeH^+, where the dissociative resonance state is absent. The nonadiabatic coupling between the dissociative states could be represented by introducing the idea of closed dissociative channel. The present calculation reproduce the experimental spectrum and isotope dependence for the first time.