[gmx-users] Gibbs free energy

[David van der Spoel]

Den 2018-03-06 kl. 08:46, skrev dina dusti:
> Dear Gromacs users
> I have one question about obtaining of Gibbs free energy. I have one micellization system in NPT ensamble. Can I obtain the Gibbs free energy by G=H-TS? When H is obtained from g_energy and selection of enthalpy and S is obtained from g_covar+g_anaeig.May I ask you to guide me, Please?
> Dina
> 
You can not get absolute entropies from gmx covar and anaeig. In theory 
you could try to estimate the entropy in the micellar state and in the 
state with dissolved lipids, but since the latter is not an equilibrium 
state you will not get anything quantitative.

A better way to estimate the DH and DS components is to pull out one 
lipid from the equilibrium micelle at different temperatures and then 
compute DH from the Van't Hoff equation.
https://en.wikipedia.org/wiki/Van_%27t_Hoff_equation

-- 
David van der Spoel, Ph.D., Professor of Biology
Head of Department, Cell & Molecular Biology, Uppsala University.
Box 596, SE-75124 Uppsala, Sweden. Phone: +46184714205.
http://www.icm.uu.se