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Ab initio geometry optimization for large molecules

✍ Scribed by Eckert, Frank; Pulay, Peter; Werner, Hans-Joachim

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 175 KB
Volume: 18
Category: Article
ISSN: 0192-8651
DOI: 10.1002/(sici)1096-987x(199709)18:12<1473::aid-jcc5>3.0.co;2-g

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✦ Synopsis

Various geometry optimization techniques are systematically Ž . investigated. The rational function RF and direct inversion in the iterative Ž . subspace DIIS methods are compared and optimized for the purpose of geometry optimization. Various step restriction and line search procedures are tested. The model Hessian recently proposed by Lindh et al. has been used in conjunction with different Hessian update procedures.

Optimization for over 30 molecules have been performed in Z-matrix coordinates, local normal coordinates, and curvilinear natural internal coordinates, using the same approximations for the Hessian in all cases. The most effective and stable procedure for optimization of equilibrium structures was found to be the DIIS minimization in natural internal coordinates using the BFGS update of the model Hessian. Our method shows faster overall convergence than all previously published methods for the same test suite of molecules.

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