2003 Fiscal Year Final Research Report Summary
Developments and applications of molecular orbital theories involving the complete basis set effects
| Project/Area Number |
13440177
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | Nagoya University |
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Principal Investigator |
TEN-NO Seiichiro Nagoya University, Graduate School of Information Science, Associate Professor, 大学院・情報科学研究科, 助教授 (00270471)
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| Co-Investigator(Kenkyū-buntansha) |
YASUDA Koji Nagoya University, Graduate School of Information Science, Associate Professor, 大学院・情報科学研究科, 助手 (70293686)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Correlation Factor / Cusp Conditions / Many Electron Theory / Geminals / Density Fitting / Numerical Integration / Density Functional Theory |
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| Research Abstract |
1. We developed explicitly correlated methods based on the similarity transformed Hamiltonian. The convergence of electron correlation is improved significantly in the second order perturbation theory and the linearized coupled cluster method.
2. We proposed a rational generator for the s-and p-wave cusp conditions and applied it to the second order perturbation theory. The density fitting and numerical integration techniques for three-electron integrals are also developed and proved to be more efficient than the conventional RI approximation. The method is successfully applied to the calculation of various reaction enthalpies.
3. Positronium atoms are calculated with explicitly correlated methods. It is shown that the present method estimates positron affinities more accurately than the orbital-based perturbation theory.
4. We developed a first principle quantum/classical mechanical (QM/MM) method. By the use of an effective Hamiltonian based on the minimum energy principle, the double-counting and boundary problems are avoided. The way to extend the QM/MM method to conjugated systems at correlated levels is clarified.
5. A general way to determine the model Hamiltonian is proposed. The model Hamiltonian gives the same excitation energies and density matrix for an approximation of the true Hamiltonian. We applied the method to the Hubbard Hamiltonian for the iso-nuclear diatomic molecule to reproduce the electron correlation accurately.
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