[gmx-users] Solvation Free Energy Calculation

[Emanuel Birru]

Hi 

I am using Gromacs to calculate solvation of free energy calculation. First I tried the tutorial I found on the following link and run all the simulations for different lambda values 36 run for both in water and in vacuum and I got 25215.67 is gromacs calculate this in J or KJ? Even if it in J its way far from the toluene solvation of free energy (-3.1KJ/mol). I got some warnings while I was running the g_analyze which says  "tau2 is longer than the length of the data (100) invalid fit (statistics might be bad) will fix tau2 at the total time 100", I got this warning for few runs not for all the runs.

Any suggestion,
Cheers