posted on 2021-02-04, 19:05authored byAjeet
Kumar Yadav, Pradipta Bandyopadhyay, Tomaz Urbic, Ken A. Dill
A goal in computational chemistry
is computing hydration free energies
of nonpolar and charged solutes accurately, but with much greater
computational speeds than in today’s explicit-water simulations.
Here, we take one step in that direction: a simple model of solvating
waters that is analytical and thus essentially instantaneous to compute.
Each water molecule is a 2-dimensional dipolar hydrogen-bonding disk
that interacts around small circular solutes with different nonpolar
and charge interactions. The model gives good qualitative agreement
with experiments. As a function of the solute radius, it gives the
solvation free energy, enthalpy and entropy as a function of temperature
for the inert gas series Ne, Ar, Kr, and Xe. For anions and cations,
it captures relatively well the trends versus ion radius. This approach
should be readily generalizable to three dimensions.