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
A technique for orbital exponent optimization in ab initio HFSCFLCAOMO calculations
β Scribed by G. M. Loubriel; R. G. Selsby
- Publisher
- John Wiley and Sons
- Year
- 1974
- Tongue
- English
- Weight
- 497 KB
- Volume
- 8
- Category
- Article
- ISSN
- 0020-7608
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
A technique for Slater orbital exponent optimization in an HFο£ΏSCFο£ΏLCAOο£ΏMO calculation is proposed in which orbital exponent variation is incorporated into the SCF scheme. This is accomplished by rewriting Slater's rules so that the shielding terms depend on the molecular charge distribution through the elements of the population matrix. The SCF scheme then includes a calculation of a new set of orbital exponents from the coefficients of selfβconsistent molecular orbitals obtained from the previous set of exponents. The process is iterated until the energy attains its lowest value.
The technique is illustrated by minimal basis calculations on LiH, BH, and HF. Near optimization is obtained with considerably less effort than is necessary for other reported techniques. Aside from interesting properties, the technique can be important for extended basis calculations where exponent optimization is a difficult task.
π SIMILAR VOLUMES
## Abstract A new computational scheme integrating ab initio multicenter molecular orbitals for determining forces of individual atoms in large cluster systems is presented. This method can be used to treat systems of many molecules, such as solvents by quantum mechanics. The geometry parameters ob