Geometry optimization using the elongation
method is developed at the Hartree–Fock level of theory.
The formalism of elongation energy gradient and its
accuracy have been validated by model systems calcula-
tions. The linear poly-hydrogen fluoride, polyethylene,
planar polyacetylene and extended polyalanine are opti-
mized using different basis sets and compared with con-
ventional results. The results show that the elongation
Hartree–Fock geometry optimization (ELG-HF-OPT) can
reproduce conventional calculation results with high
accuracy for various basis sets. For the poly-hydrogen fluoride calculation at 6-31G(d,p) basis set, moreover,
ELG-HF-OPT gives a structure with lower ground state
energy than conventional results with the same optimiza-
tion convergence threshold. This means the potential pos-
sibility of ELG-HF-OPT can locate a more stable structure
than conventional calculations with the same optimization
convergence criteria. Therefore, the ELG-HF-OPT would
provide one more choice for performing optimization on
complicated large systems.
keywords in English:
Geometry optimization, Cutoff technique, Elongation method, Large system
departmental parameterization:
30
affiliation:
Wydział Chemii : Zakład Chemii Teoretycznej im. K. Gumińskiego