title: 1.14*CM1A-LBCC: Localized Bond-Charge Corrected CM1A Charges for Condensed-Phase Simulations.
abstract: The quality of the 1.14*CM1A and 1.20*CM5 charge models was evaluated for calculations of free energies of hydration. For a set of 426 neutral molecules, 1.14*CM1A and 1.20*CM5 yield MADs of 1.26 and 1.21 kcal/mol, respectively. The 1.14*CM1A charges, which can be readily obtained for large systems, exhibit large deviations only for a subset of functional groups. The results for these cases were systematically improved using localized bond-charge corrections (LBCC) by which offsetting adjustments are made to the partial charges for atoms in specified bond types. Only 19 LBCCs were needed to yield 1.14*CM1A-LBCC charges that reduce the errors for the 426 ΔGhydvalues to only 0.61 kcal/mol. The modified charge method was also tested in computation of heats of vaporization and densities for pure organic liquids, yielding average errors of 1.40 kcal/mol and 0.024 g/cm3, similar to those for 1.14*CM1A.
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
authors.forename: Leela S
authors.initials: LS
authors.lastname: Dodda
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
authors.forename: Jonah Z
authors.initials: JZ
authors.lastname: Vilseck
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
authors.forename: Julian
authors.identifier: 0000-0001-7330-189X
authors.initials: J
authors.lastname: Tirado-Rives
authors.affiliation: Department of Chemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
authors.forename: William L
authors.identifier: 0000-0002-3993-9520
authors.initials: WL
authors.lastname: Jorgensen
mesh_terms: D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water