"Flexibility does not change the polarizability of water molecules in the liquid" Bernhard Schropp and Paul Tavan
J. Phys. Chem. B 114, 2051-2057 (2010)
Abstract: Molecular mechanics (MM) force fields employed in molecular dynamics simulations of bulk liquid water or of solvated proteins have to appropriately handle the sizeable polarizability α of the water molecules. Using a hybrid method that combines density functional theory (DFT) for a rigid water molecule with an MM description of the liquid environment we have recently shown that the induced dipole moment can be accurately calculated by linear response
multiplying the experimental gas phase polarizability αexp with the electric reaction field averaged over the volume of the molecule [B.Schropp and P. Tavan, J. Phys. Chem. B 112, 6233 (2008)]. However, water molecules are flexible and the strong local fields acting in the liquid can change their geometries. These changes of geometry can modify both the dipole moment and the polarizability. Using a DFT/MM approach for a flexible DFT water model here we show that the corresponding effects cancel. As a result, rigid, transferable, and
polarizable MM models automatically include the couplings between the external field in the bulk liquid, the geometry, and the dipole moment of an embedded water molecule.
BMO authors (in alphabetic order): Bernhard Schropp Paul Tavan
Assoziierte Projekte: Polarizable force fields for molecular mechanics from first principles
WWW-Version
|