An improved multistate empirical valence bond model for aqueous proton solvation and transport.
A new multistate empirical valence bond model (MS-EVB3) is developed for proton solvation and transport in aqueous solutions. The new model and its quantum version (qMS-EVB3) are based on the MS-EVB2 model [Day et al., J. Chem. Phys. 2002, 117, 5839] and recently developed flexible water models-the SPC/Fw model [Wu et al. J. Chem. Phys. 2006, 124, 24503] and the qSPC/Fw model [Paesani et al. J. Chem. Phys. 2006, 125, 184507]-for classical and quantum simulations, respectively. Using ab initio data as benchmarks, the binding energies and optimized geometries calculated with the new model for protonated water clusters, as well as the potential energy surface for proton shuttling between water molecules in a cluster environment, are improved in comparison to the MS-EVB2 model. For aqueous solutions, classical and quantum molecular dynamics simulations with the MS-EVB3 model yield a more accurate description of the solvation structure and diffusive dynamics of the excess proton. New insight is also provided into the proton solvation and hopping dynamics in water, as well as the "amphiphilic" nature of the hydrated proton that has been predicted to give rise to its enhanced concentration at aqueous interfaces and an effectively lower pH of the air-water interface [Petersen et al. J. Phys. Chem. B 2004, 108, 14804].
Wu
Yujie
Y
Department of Chemistry and Center for Biophysical Modeling and Simulation, University of Utah, 315 South 1400 East, Room 2020, Salt Lake City, Utah 84112-0850, USA.
Chen
Hanning
H
Wang
Feng
F
Paesani
Francesco
F
Voth
Gregory A
GA
D003198:Computer Simulation; D004058:Diffusion; D006860:Hydrogen Bonding; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D012995:Solubility; D012997:Solvents; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry
D011522:Protons; D012997:Solvents; D014867:Water