1998 Fiscal Year Final Research Report Summary
Theoretical Study on the Photoreactions of Biological Compounds
| Project/Area Number |
09450314
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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 |
工業物理化学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
HIRAO Kimihiko The University of Tokyo, Graduate School of Engineering, Professor, 大学院・工学系研究科, 教授 (70093169)
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| Co-Investigator(Kenkyū-buntansha) |
TAKETSUGU Tetsuya The University of Tokyo, Graduate School of Engineering, Assistant Professor, 大学院・工学系研究科, 助手 (90280932)
NAKANO Haruyuki The University of Tokyo, Graduate School of Engineering, Lecturer, 大学院・工学系研究科, 講師 (90251363)
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| Project Period (FY) |
1997 – 1998
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| Keywords | MRMP / CASVB / Excited states / Alternant hydrocarbon / porphyrin / OP / RESC / Molecular Integrals |
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| Research Abstract |
Our Multireference Moller-Plesset (MRMP) theory is an extension of the closed-shell single reference MP method and has been successfully applied to numerous chemical and spectroscopic problems. MRMP has established through this study as an efficient technique for treating both dynamical and nondynamical correlation effects. MRMP was applied to the study of the valence pi*pi^* excited states of polyenes, polyacenes, and porphyrins. MRMP satisfactorily describes the ordering of low-lying valence pi*pi^* excited states for alternant hydrocarbons. MRMP predicts the valence excitation energies with an accuracy of 0.2 eV or better. The MRMP approach with the alternant pairing properties has proved to be of great value in understanding and predicting the experimental data of the alternant hydrocarbons. The conclusion derived in this study is to some extent transferable and thus provides a reasonable basis for a description of the excited states of other larger polyenes, polyacenes and porphyr
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ins. We have also proposed a complete active space valence bond (CASVB) method. A CASVB wave function can be obtained simply by transforming a canonical CASSCF function and readily interpreted in terms of the well-known classical VB resonance structures. The CASVB affords a clear view of the wave functions for the various states. In addition, we have proposed several new theory and concepts : MRMP in the extended basis function space (EBS), relativistic MRMP with a new relativistic scheme by eliminating small-component (RESC) of the four-component Dirac equation. EBS-MRMP is a theory based on a concept of different bases for different correlation effects. The new RESC-scheme is a very promising alternative to the Dirac method. We have also proposed a new simplified Colle-Salvetti-type correlation functional called OP in density functional theory. OP includes only one-parameter and no adjusted functional constant. OP satisfies all the necessary conditions of the exact correlation functional. OP is proved to give more accurate correlation energies for atoms and equivalent chemical properties for G2 set of molecules. Less
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Research Products
(12 results)
