Constructing theoretical atomic spectra and molecular wave functions on the Schroedinger-level accuracy

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K21182
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 32:Physical chemistry, functional solid state chemistry, and related fields
• Research Institution: Quantum Chemistry Research Institute
• Principal Investigator: Nakashima Hiroyuki 認定NPO法人量子化学研究協会, 研究所, 部門長 (80447911)
• Project Period (FY): 2020-07-30 – 2022-03-31
• Keywords: シュレーディンガー方程式 / 自由完員関数理論 / 理論原子スペクトル / 分子波動関数

Outline of Final Research Achievements

We developed the computational theory and program of the variational free complement theory for solving the Schroedinger equations of atoms and molecules. In the application to a carbon atom, the chemical accuracy as absolute solution was obtained even with only small number of freedoms. The excitation energies of various quantum states were also reproduced in a very good correspondence with the experimental Moore’s table. In the application to a C2 molecule, the potential energy curves of the ground and low-lying excited states were accurately calculated and their chemical natures were analyzed along the reaction coordinate based on a local picture.

Free Research Field

量子化学、計算科学

Academic Significance and Societal Importance of the Research Achievements

量子力学の基礎方程式であるシュレーディンガー方程式の正確な解を求めることができれば、理論によってあらゆる化学現象を予言することができる。本研究では、その正確な解を導く自由完員関数理論に基づき、その変分法の計算に必要な方法論と計算プログラムを開発した。応用は基礎的な原子・分子に限られたが、正確であるだけでなく理解に繋げられる局所的波動関数を計算することができ、その成果は原子の量子状態と分子の化学結合の本質的な理解と発展に繋げられる意義がある。