Affordable Access

Optimization of force constants with an Urey-Bradley force field avoiding normal mode crossings.

Authors
  • Vivoni, A
  • Birke, R
  • Lombardi, J
Type
Published Article
Journal
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy
Publisher
Elsevier
Publication Date
Mar 01, 2001
Volume
57
Issue
3
Pages
535–544
Identifiers
PMID: 11300565
Source
Medline
License
Unknown

Abstract

We present a method that simplifies the refinement of force constants in normal mode calculations and makes the results more reliable. The method avoids normal mode crossings by constraining the force constants during refinement. It was tested with pyrrole, imidazole, benzene, pyridine, pyrimidine, aniline and adenine using a Urey-Bradley force field. The global error of the frequency fit for these molecules was 0.61%. The method reproduced with fewer parameters the accuracy of similar calculations of the single ring aromatic compounds. It improved the accuracy and isotopic shifts of previous empirical calculations of adenine by 40%. The C-C and C-N stretchings differed by less than 7% from the values of force constant-bond length empirical relations.

Report this publication

Statistics

Seen <100 times