A molecular dynamics study of water nucleation using the TIP4P/2005 model.
Extensive molecular dynamics simulations were conducted using the TIP4P/2005 water model of Abascal and Vega [J. Chem. Phys. 123, 234505 (2005)] to investigate its condensation from supersaturated vapor to liquid at 330 K. The mean first passage time method [J. Wedekind, R. Strey, and D. Reguera, J. Chem. Phys. 126, 134103 (2007); L. S. Bartell and D. T. Wu, 125, 194503 (2006)] was used to analyze the influence of finite size effects, thermostats, and charged species on the nucleation dynamics. We find that the Nosé-Hoover thermostat and the one proposed by Bussi et al. [J. Chem. Phys. 126, 014101 (2007)] give essentially the same averages. We identify the maximum thermostat coupling time to guarantee proper thermostating for these simulations. The presence of charged species has a dramatic impact on the dynamics, inducing a marked change towards a pure growth regime, which highlights the importance of ions in the formation of liquid droplets in the atmosphere. It was found a small but noticeable sign preference at intermediate cluster sizes (between 5 and 30 water molecules) corresponding mostly to the formation of the second solvation shell around the ion. The TIP4P/2005 water model predicts that anions induce faster formation of water clusters than cations of the same magnitude of charge.
Nano-bio Spectroscopy Group and ETSF Scientific Development Center, Department of Materials Science, Faculty of Chemistry, University of the Basque Country (UPV/EHU), Donostia-San Sebastián, Spain. alejandroperezpaz@yahoo.com
Alejandro
A
Pérez
Angel
A
Rubio
D056004:Molecular Dynamics Simulation; D012996:Solutions / Q000737:chemistry; D013227:Steam / Q000032:analysis; D013696:Temperature; D014867:Water / Q000737:chemistry*
D012996:Solutions; D013227:Steam; D014867:Water