Theoretical study of resonance states and photoionization of atoms and molecules

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05668
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Keio University
• Principal Investigator: Yabushita Satoshi 慶應義塾大学, 理工学部(矢上), 教授 (50210315)
• Co-Investigator(Kenkyū-buntansha): 岩田 末廣 慶應義塾大学, 理工学部(矢上), 訪問教授 (20087505)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 複素基底関数法 / 光イオン化微分断面積 / ２ポテンシャル公式 / 振動数依存分極率 / 相対論効果 / 多極子展開 / 局所射影分子軌道摂動論 / 分子間相互作用理論

Outline of Final Research Achievements

Boundary conditions satisfied by continuum states at the asymptotic region are essential for the discussion of differential cross sections, and have been a long-standing obstacle to some L2 methods. To solve this problem, we rely on the so-called two-potential formula to represent transition moments, and apply the complex basis function (CBF) method to solve the driven-type Schrödinger equation for photoionization differential cross sections.
The K-shell photoionization cross sections of the one-electron uranium cation have been studied using the inhomogeneous Dirac equation. The total and differential cross sections showed good agreement with the previous theoretical values and also with experimental values for the neutral uranium atom, emphasizing the importance of the multipole effect of electromagnetic fields, and significant effects caused by the small component wave functions. These results demonstrated the effectiveness of the CBF method in relativistic treatment.

Free Research Field

理論化学

Academic Significance and Societal Importance of the Research Achievements

古くから多くの研究分野で物質の構成元素やその化学環境を調べるためにX線光電子分光法（XPS）が利用されてきた。特に最近の極短時間計測法では、光電子角度分布の測定を通して、分子構造の時間変化が議論されている。微分断面積の評価は容易でないが、将来的にはこのような研究分野に有用な基礎情報を提供できると期待される。