Systematic Parameterization of Monovalent Ions Employing the Nonbonded Model

作者：Li, Pengfei; Song, Lin Frank; Merz, Kenneth M., Jr.^*

来源：Journal of Chemical Theory and Computation, 2015, 11(4): 1645-1657.

DOI：10.1021/ct500918t

• FREE-ENERGY CALCULATIONS
• HYDRATION FREE-ENERGY
• PARTICLE MESH EWALD
• MOLECULAR-DYNAMICS SIMULATION
• GIBBS FREE-ENERGY
• FORCE-FIELD
• THERMODYNAMIC INTEGRATION
• ALKALI-METAL
• COMPUTER-SIMULATIONS
• ELECTRONIC-STRUCTURE

Monovalent ions play fundamental roles in many biological processes in organisms. Modeling these ions in molecular simulations continues to be a challenging problem. The 12-6 Lennard-Jones (LJ) nonbonded model is widely used to model monovalent ions in classical molecular dynamics simulations. A lot of parameterization efforts have been reported for these ions with a number of experimental end points. However, some reported parameter sets do not have a good balance between the two Lennard-Jones parameters (the van der Waals (VDW) radius and potential well depth), which affects their transferability. In the present work, via the use of a noble gas curve we fitted in former work ( J. Chem. Theory Comput. 2013, 9, 2733), we reoptimized the 12-6 LJ parameters for 15 monovalent ions (11 positive and 4 negative ions) for three extensively used water models (TIP3P, SPC/E, and TIP4P(EW)). Since the 12-6 LJ nonbonded model performs poorly in some instances for these ions, we have also parameterized the 12-6-4 LJ-type nonbonded model ( J. Chem. Theory Comput. 2014, 10, 289) using the same three water models. The three derived parameter sets focused on reproducing the hydration free energies (the HFE set) and the ion-oxygen distance (the IOD set) using the 12-6 LJ nonbonded model and the 12-6-4 LJ-type nonbonded model (the 12-6-4 set) overall give improved results. In particular, the final parameter sets showed better agreement with quantum mechanically calculated VDW radii and improved transferability to ion-pair solutions when compared to previous parameter sets.

• 出版日期2015-4