A scheme for rapid evaluation of the intermolecular three‐body polarization effect in water clusters

The ability to accurately and rapidly evaluate the intermolecular many‐body polarization effect of the water system is very important for computer simulations of biomolecule in aqueous. In this paper, a scheme is proposed based on the polarizable dipole–dipole interaction model and used to rapidly estimate the intermolecular many‐body polarization effect in water clusters. We use a bond‐dipole‐based polarization function to evaluate the polarization energy. We regard two OH bonds of a water molecule as two bond‐dipoles and set the permanent OH bond‐dipole moment of a water molecule to be 1.51 Debye. We estimate the induced OH bond‐dipole moment via a simple formula in which only one correction factor is needed. This scheme is then applied to tens of water clusters to calculate the three‐ and four‐body interaction energies. The three‐body interaction energies of 93 water clusters produced by our scheme are compared with those produced by the counterpoise‐corrected CCSD(T)/aug‐cc‐pVDZ, MP2/aug‐cc‐pVDZ, M06‐2X/jul‐cc‐pVTZ methods, by the AMOEBApro13, iAMOEBA, AMOEBA+, AMOEBA+(CF) methods, and by the MB‐pol method. The four‐body interaction energies of 47 water clusters yielded by our scheme are compared with those yielded by the counterpoise‐corrected MP2/aug‐cc‐pVDZ and M06‐2X/ jul‐cc‐pVTZ methods, by the AMOEBApro13, AMOEBA+, AMOEBA+(CF) methods, and by the MB‐pol method. The comparison results show that the scheme proposed in this paper can reproduce the counterpoise‐corrected CCSD(T)/aug‐cc‐pVDZ three‐body interaction energies and reproduce the counterpoise‐corrected MP2/aug‐cc‐pVDZ four‐body interaction energies both accurately and efficiently. We anticipate the scheme proposed here can be useful for computer simulations of liquid water and aqueous solutions. A scheme based on chemical bond dipoles is proposed and used to rapidly estimate the intermolecular many‐body polarization effect in water clusters.