1990 Fiscal Year Final Research Report Summary
The Development of a Common and HighSpeed Method of Computing Various Kind of Molecular Integrals and Theoretical Study of Iron Porphyrins
Project/Area Number 
01540397

Research Category 
GrantinAid for General Scientific Research (C)

Allocation Type  Singleyear Grants 
Research Field 
構造化学

Research Institution  Kyoto University 
Principal Investigator 
OBARA Shigeru Kyoto University, Chemistry, Assistant > 京都大学, 理学部, 助手 (80160935)

Project Period (FY) 
1989 – 1990

Keywords  Molecular Integral / Highspeed Computation / Geometry Optimization / Energy Derivatives 
Research Abstract 
In the present research, two new methods are developed, which are essentially necessary for the theoretical studies of molecular structures and chemical reactions of large molecular systems such as iron porphyrins : one is a highspeed computational method of evaluating twoelectron integrals, as well as oneelectron intregrals, and their derivatives with respect to atomic coordinates. The other is an efficient and stable method of searching for optimum structures of molecules containing cyclic parts. Any kind of molecular integrals are found to be reducible from an integral termed basic integral which satisfies recurrence relations. Then, any kind of molecular integrals can be expressed in recursive forms, so that one can carry out the recursive computation which is well known as one of the most efficient computational methods. The computations are found to be vectorizable and result in a twentyeight times faster evaluation of electron repulsion integrals for cyclohexane. The new method of searching for optimum structures aviods the difficulties in the usually used methods ; disastrous deformations occurring at cyclic parts in the method optimizing only the internal coordinates, and inefficiency in the method employing only the Cartesian coordinates. The method is found to result in optimum structures of ethylene oxide and pyridine stably and effeciently, and its usefulness is confirmed by optimizing the structure of a free base porphine.

Research Products
(4 results)