First Place
Lauren Zakrzewski
Research Project Title: Impact of Alkali Halide Salt Ions on Hydrogen Bonding at the Air-Water Interface
Abstract
We present a computational study of the effect of various ions on hydrogen bonding at the water-air interface. Molecular dynamics simulations were performed using the CHARMM force field and TIP3P water. Simulations explored the impact of temperature and concentration on hydrogen bonding near the liquid-vapor interface of aqueous NaCl, KCl, RbCl, and CsCl solutions. Average coordination number was found to increase linearly with NaCl concentration, but decrease linearly with KCl, RbCl, and CsCl concentrations for several temperatures between 10-80˚C. Density profiles across the liquid-vapor interface, water molecule orientations at this liquid-vapor interface, and surface tensions were calculated for each system.
Faculty Sponsor: Brad Bauer, Chemistry
Second Place
Gregory M. John
Research Project Title: Molecular Dynamics Simulations of Small Hydrophobes in H2O Using CHARMM
Abstract
The interactions between small hydrophobes in water were examined using molecular dynamics simulations via CHARMM. The hydrophobes investigated resembled He, Ar, and Kr and were simulated over a range of concentrations from 0.5 to 6.5 molal. Radial distribution functions showed trends at high concentrations which were different from those seen at low concentrations. The concentration at which the transition from one trend to the other takes place was found to correlate negatively with the size of the hydrophobe. This effect was investigated additionally via Gibbs free energy plots and visualization snapshots rendered with VMD.
Faculty Sponsor: Brad Bauer, Chemistry