Efficient particle-mesh Ewald based approach to fixed and induced dipolar interactions

We have implemented classical Ewald and particle-mesh Ewald (PME) based tre atments of fixed and induced point dipoles into the sander molecular dynami cs (MD) module of AMBER 6. During MD the induced dipoles can be propagated along with the atomic positions either by iteration to self-consistency at each time step, or by a Car-Parrinello (CP) technique using an extended Lag rangian formalism. In this paper we present the derivation of the new algor ithms and compare the various options with respect to accuracy, efficiency, and effect on calculated properties of a polarizable water model. The use of PME for electrostatics of fixed charges and induced dipoles together wit h a CP treatment of dipole propagation in MD simulations leads to a cost ov erhead of only 33% above that of MD simulations using standard PME with fix ed charges, allowing the study of polarizability in large macromolecular sy stems. (C) 2000 American Institute of Physics. [S0021- 9606(00)50547-9].