太阳风离子同天体环境中的原子分子碰撞过程理论研究

There has been significant progress in x-ray astrophysics over the last decade and rich X-rays have been observed from the heliosphere and extended planetary atmospheres. The origin of these emissions is believed due to the charge exchange of solar wind (SW) ions with ambient neutral species. Accurate charge exchange cross sections, expecially the state-resolved cross sections, are requrired in modeling of SWCX X-ray. However, it is challenging task to treat solar wind ions colliding with multi-electron atom and molecule, in which the high excited states sturctures of the multi-electron molecules are very complicated to be computed and various channels are openned and involved including multi-electron charge exchange and ionization, autoionization, as well as dissociation process for molecule target. In this project, we propose to use molecular-orbital close-coupling (QMOCC) and time-dependent density function theory (TDDFT) methods to investigate the charge exchange and ionization processes between dominant solar wind ions and the neutral species in the heliosphere and planetary atmosphere. There are mainly four topics and objects in the prsent proposal: 1, The molecular structure code will be developed to treat the molecular highly excited sturcture; 2, The MOCC and TDDFT methods will be developed to treat the ion collisions with atom and molecules in the low and intermediate energy region; 3,The molecular structure with complex basis sets will be developed to treat the valence- or inner-shell highly excited states of molecules. 4,The QMOCC and TDDFT methods will be applied to investigate the charge exchange processes between dominant solar wind ions and the neutral species in the heliosphere and planetary atmosphere and sets of accurate charge transfer cross sections will be obtained. From the perspective of fundamental physical investigation, th project is of great interest. Meanwhile, the results of these investigations will then enable accurate modeling of SWCX allowing for investigations of the SW, the heliosphere, and planetary exospheres.

近年来在日光层和行星大气中发现的丰富X射线，被认为源于高电荷态太阳风离子同星际大气的碰撞电荷转移过程。从基础研究上来讲，高电荷态离子同中性原子分子的碰撞研究具有很大挑战性，结构上需要精确计算碰撞体系高激发态势能面和耦合矩阵元，碰撞动力学涉及多电荷转移、多电荷电离和电荷转移自电离，对分子靶涉及到碰撞解离等过程。本项目将开展以下几方面研究：1，发展分子结构计算程序，研究分子高激发态结构；2，发展分子轨道强耦合方法和含时密度泛函方法程序，研究中低能高电荷态离子同中性原子分子碰撞动力学过程；3，发展复坐标空间分子结构计算程序，处理分子超激发态结构和内壳层电子激发的自电离态结构；4，系统计算太阳风离子同日光层和行星大气中的中性粒子碰撞电荷转移截面。该项目研究具有重要的科学意义，上述研究内容都是原子分子物理研究的前沿热点问题。同时，项目的研究将为太阳风X射线模拟提供亟需的精确电荷转移截面参数。

本项目针对高电荷态太阳风离子与天体环境中的中性原子分子(H、He、H2等)碰撞过程研究中涉及的高激发态分子结构计算和电荷转移过程中的电子关联效应发展理论模型和计算方法。结合多组态自洽和组态相互作用方法，发展方法和程序处理分子高激发态结构；发展复标度和复吸收势方法和程序，处理小分子超激发态/自电离态共振态；发展了分子轨道强耦合方法处理低能区高电荷态离子-原子/分子碰撞过程，发展含时密度泛函结合分子动力学方法处理重粒子碰撞多电子过程，发展多活跃电子原子轨道强耦合方法处理中低能区离子-原子/分子碰撞中的电子关联效应。在分子结构和散射方法发展的基础上，开展了高电荷态离子同中性原子分子碰撞系统研究，获得高置信度的碰撞电荷转移截面参数。通过本项目研究，我们一方面发展了自主知识产权计算程序，另一方面获得了高精度的电荷转移截面参数，可以作为天体物理中太阳风X射线模拟的标准数据。