Anharmonic Molecular Mechanics: Ab Initio Based Morse Parametrizations for the Popular MM3 Force Field

R. J. Shannon*, B. Hornung, D. P. Tew, D. R. Glowacki

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

8 Citations (Scopus)
91 Downloads (Pure)


Methodologies for creating reactive potential energy surfaces from molecular mechanics force-fields are becoming increasingly popular. To date, molecular mechanics force-fields in biochemistry and small molecule organic chemistry tend to use harmonic expressions to treat bonding stretches, which is a poor approximation in reactive and nonequilibirum molecular dynamics simulations since bonds are often displaced significantly from their equilibrium positions. For such applications there is need for a better treatment of anharmonicity. In this contribution, Morse bonding potentials have been extensively parametrised for the atom types in the MM3 force field of Allinger and co-workers using high level CCSD(T)(F12∗) energies. To our knowledge this is among the first instances of a comprehensive parametrisation of Morse potentials in a popular organic chemistry force field. In the context of molecular dynamics simulations, these data will: (1) facilitate the fitting of reactive potential energy surfaces using empirical valence bond approaches and (2) enable more accurate treatments of energy transfer.

Original languageEnglish
Pages (from-to)2991-2999
Number of pages9
JournalJournal of Physical Chemistry A
Issue number13
Early online date22 Feb 2019
Publication statusPublished - 4 Apr 2019


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