Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Importance of Excluded Volume on the Solvation of Urea in Water



Raymond D. Mountain, D Thirumalai


We have used molecular dynamics simulations to probe the concentration-dependent solvation of urea in water. Two models of urea re considered: one of the in the OPLS potential and the other is the recently introduced KBFF model whose parameters were obtained to reproduce the experimental values of the Kirkwood-Buff integrals. Although the partial charges on the urea atoms in the models are dramatically different the concentration dependent structural characteristics of water is similar. The largest difference between the two models is in the prediction of the tendency of urea to self-associate. The OPLS model leads to stronger urea-urea association than the KBFF model. Surprisingly, this difference is traced to the variations in the Lennard-Jones parameters rather than the charge distributions. These results suggest that solvation of urea depends not only on its ability to form hydrogen bonds with water but also its excluded volume. More generally we propose that denaturation efficiency of polar non-electrolytes, such as urea, is determined by the ability of the cosolute to form hydrogen bonds with the polypeptide chain which in turn depends on its size.
Journal of Physical Chemistry B
No. 21


electrostatic interaction, excluded volume, hydrogen bond, molecular dynamics, solvation, urea


Mountain, R. and Thirumalai, D. (2004), Importance of Excluded Volume on the Solvation of Urea in Water, Journal of Physical Chemistry B (Accessed July 12, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created May 1, 2004, Updated February 17, 2017