Geometry optimizations being still very time-consumin s, methods are imrstigated to sa%e time .tt least in spcci.d cases. The Hellmzutn-Fejnmzm force is reconsidered as 3x1 approximation to the energy gradrent .md is found useful for the first few iterations of a Fometry optimization for molecules h
Geometry optimization in ab initio molecular orbital theory
β Scribed by Dieter Poppinger
- Publisher
- Elsevier Science
- Year
- 1975
- Tongue
- English
- Weight
- 424 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0009-2614
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β¦ Synopsis
A gradient optimization procedure has been used to calculate equilibrium geometries for several small molecules in the framework of ab initio molecular orbital theory. The gradient method was found to be faster and more reliable than two direcl search procedures.
π SIMILAR VOLUMES
## Abstract We present several variants of methods for the automatic search of optimum geometries of solutes via __ab initio__ SCF procedures. The physical meaning of geometry optimization in solution is discussed. Advantages and disadvantages of the different variants are shown making use of calcu
The crucial role of including d-orbital in predicting geometries of molecuies containing second row atoms in the usual ntom-centred LCAO MO ab initio method is critically discussed. Examples are taken from the lirerature and from calculations on H2S, MeSH and FSN\_employing a variety of basis sets.
Various geometry optimization techniques are systematically Ε½ . investigated. The rational function RF and direct inversion in the iterative Ε½ . subspace DIIS methods are compared and optimized for the purpose of geometry optimization. Various step restriction and line search procedures are tested.
## Abstract The molecular geometry of 1βfluorosilatrane was optimized fully by restricted HartreeβFock (HF) calculations using the 3β21G, 3β21G(__d__) and 6β31G(__d__) basis sets, with the aim of locating the positions of the local minima on the energy hypersurface. The optimized geometries were co