Name
Title | ||
|---|---|---|
Molecular mechanics (MM4) vibrational frequency calculations for alkenes and conjugated hydrocarbons |
Abstract | ||
|---|---|---|
Vibrational frequencies for 11 alkenes and 8 conjugated hydrocarbons have been analyzed with MM4. The root mean square (rms) difference between the experimental and MM4 values is 25 cm(-1) for seven alkenes and 31 cm(-1) for eight conjugated hydrocarbons, compared to MM3 rms differences of 38 cm(-1) for alkenes and 52 cm(-1) for conjugated hydrocarbons. New MM4 cross-terms which primarily affect vibrational frequencies include bend-torsion-bend, improper torsion-torsion-improper torsion, and stretch-stretch, which imp rove in-plane bending, out-of-plane bending, and stretching frequencies, respectively. The stretching force parameter for conjugated bonds has been changed to vary quadratically with bond order (instead of linearly, as in MM3). The addition of a V4 term to the torsional potential for alkenes and conjugated hydrocarbons helps improve torsional frequencies. The torsion-torsion cross-term increases out-of-plane bending frequencies in conjugated hydrocarbons. This overall improvement in the vibrational frequencies does not result in any sacrifice in the accuracy of other quantities calculated by MM4. (C) 1996 by John Wiley & Sons, Inc. |
Year | DOI | Venue |
|---|---|---|
1996 | 10.1002/(SICI)1096-987X(199604)17:6<730::AID-JCC9>3.3.CO;2-4 | JOURNAL OF COMPUTATIONAL CHEMISTRY |
Keywords | Field | DocType |
molecular mechanics | Bond order,Torsion (mechanics),Computational chemistry,Chemistry,Bending,Root mean square,Molecular vibration,Conjugated system | Journal |
Volume | Issue | ISSN |
17.0 | 5-6 | 0192-8651 |
Citations | PageRank | References |
13 | 1.61 | 0 |
Authors | ||
2 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Neysa Nevins | 1 | 35 | 4.60 |
| Norman L. Allinger | 2 | 212 | 36.95 |