原子能级和辐射跃迁几率是天体物理中重要的原子参数。利用多组态Dirac-Fock方法，加入Breit相互作用、量子电动力学(QED)效应和核运动效应等高阶修正项，我们计算了OII的基态组态(1s22s22p3)的精细结构能级。在充分地考虑了电子关联作用的基础上，我们讨论了各种高阶修正项对原子精细结构能级的影响，阐明了Breit相互作用（即电磁相互作用的相对论延迟效应）会导致原子的精细结构能级分裂反转。基于高精度的原子能级和波函数，我们计算了OII的两根辐射跃迁线2D5/2,3/2 →4S3/2的E2、M1跃迁几率。我们系统地阐明了core电子激发关联作用、Breit相互作用对E2、M1跃迁几率的影响，并且利用不同基组和不同规范下的计算结果估算计算误差。最终我们给出了高密度极限下OII的辐射跃迁线强比值I(3729)/I(3726)及计算误差 ，与天文观测值0.35符合得很好。这个比值被广泛应用于诊断行状星云的电子密度。预期利用多组态Dirac-Fock方法进行精密原子结构计算可以面向精密原子测量以及基础物理中的很多问题。另一方面，基于含时波包传播理论方法，我们研究一些少电子原子分子体系的结构和动力学过程。我们发展了一种在分块网格中传播含时波包的方法，并且利用全反射边界条件，计算了H原子在全能域（包括无限Rydberg态和连续态）的光吸收振子强度密度。我们还发展了一种自洽的方法来处理质子与原子的碰撞过程：用量子波包描述电子的运动，用经典轨迹描述质子的运动。我们计算了在质子与Li原子的碰撞过程中Li原子的2s电子被激发到2p态的碰撞激发截面，与实验结果符合得很好。利用基于分离算符方案的含时波包传播方法，我们还研究了H2高能电离产物H2+的核振动末态几率分布，并且讨论了其同位素效应。我们发展的含时波包传播方法可以面向强激光场作用下的原子分子的各种动力学过程。
Atomic energy levels and radiation transition rates are important atomic data for astrophysics. Using multi-configuration Dirac-Fock (MCDF) method with high-order corrections such as Breit interactions, quantum electrodynamics (QED) corrections and nuclear motion corrections, we have calculated the fine-structure energy levels of the ground configuration (1s22s22p3) of OII. We take adequate electron correlation interactions into account and elucidate that the Breit interaction is significant for the fine-structure splittings. Based on the high-quality energy levels and wave functions, we have calculated the E2 and M1 transition rates for 2D5/2,3/2 →4S3/2 of OII. We systematically elucidate that the core electron excitation correlations and the Breit interactions are important for the convergence of the transition rates. We estimate the calculation errors using different basis and different gauges. Finally we present a benchmark for the intensity ratio between the two transitions 2D5/2,3/2→4S3/2 of OII in the limit of high density, which is widely used at electron density diagnosis for planetary nebulas.We also developed time-dependent wave-packet propagation (TDWPP) methods and studied structures and dynamics of few-electron atomic and molecular systems. Based on real-space propagation scheme, we calculated the photoabsorption oscillator strength densities for hydrogen atom, including infinite Rydberg states and continuum states. We developed a self-consistent method to calculate the cross sections of proton impact excitation (2s-2p) with Lithium atom. Based on split-operator scheme, we studied the probability distributions of the final vibrational states of the product H2+ in the ionization process of H2. The TDWPP methods are flexible to deal with various atomic and molecular processes induced by intense laser fields.
