title: An extensible and systematic force field, ESFF, for molecular modeling of organic, inorganic, and organometallic systems.
abstract: ESFF is a rule-based force field designed for modeling organic, inorganic, and organometallic systems. To cover this broad range of molecular systems, ESFF was developed in an extensible and systematic manner. Several unique features were introduced including pseudoangle and a dot product function representing torsion energy terms. The partial atomic charges that are topology-dependent are determined from ab initio (DFT) calculated electronegativity and hardness for valence orbitals. The van der Waals parameters are charge-dependent, and correlated with the ionization potential for atoms in various valence states. To obtain a set of well-defined and physically meaningful parameters, ESFF employs semiempirical rules to translate atomic-based parameters to parameters typically associated with a covalent valence force field. The atomic parameters depend not only on atom type, but also on internal type, thus resulting in a more accurate force field. This article presents the theory and the method used to develop the force field. The force field has been applied to molecular simulations of a wide variety of systems including nucleic acids, peptides, hydrocarbons, porphyrins, transition metal complexes, zeolites, and organometallic compounds. Agreement with the experimental results indicates that ESFF is a valuable tool in molecular simulations for understanding and predicting both crystal and gas phase molecular structures.
authors.affiliation: Pfizer Global Research & Development, La Jolla Laboratories/Agouron Pharmaceuticals Inc, 3550 General Atomics Court, San Diego, California 92121, USA.
authors.forename: Shenghua
authors.initials: S
authors.lastname: Shi
authors.forename: Lisa
authors.initials: L
authors.lastname: Yan
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.forename: Jodi
authors.initials: J
authors.lastname: Fisher-Shaulsky
authors.forename: Tom
authors.initials: T
authors.lastname: Thacher
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D007287:Inorganic Chemicals / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009705:Nucleosides / Q000737:chemistry; D009930:Organic Chemicals; D009942:Organometallic Compounds / Q000737:chemistry; D011166:Porphyrins / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D007287:Inorganic Chemicals; D009705:Nucleosides; D009930:Organic Chemicals; D009942:Organometallic Compounds; D011166:Porphyrins