Water properties from first principles: simulations by a general-purpose quantum mechanical polarizable force field

Area of Science:

• Computational chemistry
• Molecular dynamics
• Biophysics

Background:

• Accurate molecular simulations require reliable force fields.
• Existing force fields may not capture complex phenomena like water's anomalous density.
• A quantum mechanical polarizable force field (QMPFF) was previously developed.

Purpose of the Study:

• To introduce an improved quantum mechanical polarizable force field, QMPFF2.
• To validate QMPFF2's performance in simulating liquid water.
• To assess QMPFF2's suitability for biomolecular simulations.

Main Methods:

• Development of the QMPFF2 force field using high-level quantum mechanical data.
• Application of QMPFF2 to molecular dynamics simulations of liquid water.
• Comparison of simulation results with experimental thermodynamic and structural data.

Main Results:

• QMPFF2 simulations showed excellent agreement with experimental data for water.
• QMPFF2 accurately reproduced the anomalous temperature dependence of water density.
• QMPFF2 performed comparably to or better than specialized water potentials.

Conclusions:

• QMPFF2 is a robust ab initio force field for simulating water.
• The ability to simulate both organic molecules and water makes QMPFF2 valuable for biomolecular systems.
• QMPFF2 shows promise for simulations of proteins and protein-ligand interactions.