Derivation of force fields for molecular mechanics and dynamics from ab initio energy surfaces

AUTOR(ES)

Maple, Jon R.

RESUMO

We present a technique for addressing the problem of deriving potential energy functions for the simulation of organic, polymeric, and biopolymeric systems, as well as for modeling vibrational spectroscopic properties. This method is designed to address three major objectives: deriving and comparing optimal functional forms for describing the energies of molecular deformations and interactions, developing a technique to rapidly and objectively determine reasonable force constants for intermolecular and intramolecular interactions, and determining the transferability of these potential forms and constants. The first two of these objectives are addressed in this paper, while the latter problem will be treated elsewhere. The technique uses ab initio molecular energy surfaces, which are described by the energy and its first and second derivatives with respect to coordinates. As an example, application to a small model compound (i.e., the formate anion) is given. A variety of analytical forms for the potential are tested against the data, to find which forms are best. The importance of anharmonicity and cross terms in accounting for structure and energy, as well as for dynamics, is demonstrated and a more accurate representation of the out-of-plane deformation for a trigonal center is derived from the energy surfaces.

Documentos Relacionados

• Ab initio molecular dynamics calculations of ion hydration free energies
• From ab initio quantum mechanics to molecular neurobiology: A cation–π binding site in the nicotinic receptor
• Ab initio molecular dynamics study of proton transfer in a polyglycine analog of the ion channel gramicidin A.
• Ab initio simulations of protein-folding pathways by molecular dynamics with the united-residue model of polypeptide chains
• Ab initio determination of the (100) surfaces phonon dispersions of the SiC