Premium
Molecular mechanics (MM4) calculations on alkenes
Author(s) -
Nevins Neysa,
Chen Kuohsiang,
Allinger Norman L.
Publication year - 1996
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/(sici)1096-987x(199604)17:5/6<669::aid-jcc7>3.0.co;2-s
Subject(s) - moment of inertia , bond length , torsion (gastropod) , force field (fiction) , chemistry , formalism (music) , molecular geometry , computational chemistry , molecule , molecular physics , classical mechanics , physics , quantum mechanics , organic chemistry , medicine , art , musical , surgery , visual arts
The MM4 force field has been extended to alkenes. It retains most of the formalism and computational schemes that were present in MM3. Several additional cross‐terms have been added in MM4 that were not present in MM3, mainly to improve vibrational frequencies but also to improve structures and energies. About 100 molecules have been examined, many in multiple conformations. Geometries are fit for the most part to within the following ranges: 0.004 Å for bond lengths, 1° for bond angles, 4° for torsion angles, and 0.5% for moments of inertia ( r 2 ). Conformational energy differences/barriers are generally fit to within 0.5 kcal/mol unless they are very large. The vibrational frequency rms error for 7 alkenes is 25 cm −1 . © 1996 by John Wiley & Sons, Inc.