[gmx-users] hydration free energy

[dgfd dgdfg]

| Have you tried other FE estimate algorithms (i.e. thermodynamic
>integration, MBAR, etc.). Look into the project "alchemical-analysis". It's
>a python script that will give you some good visualizations on what is
>happening at that last step (it's compatible with GROMACS output files).
>There's an associated paper with it as well.
>
>Also double check that you are somehow not mistakingly leaving on some kind
>of interaction that is blowing up after everything else is decoupled 
Indeed it is mistake in my options. No TD method can produce good result with my data.
I wasn't careful. Now I see in dhdl.xvg for lambda=100 that :

@ s0 legend "dH/d\xl\f{} coul-lambda = 1.0000"
@ s1 legend "dH/d\xl\f{} vdw-lambda = 1.0000"
@ s2 legend "\xD\f{}H \xl\f{} to (1.0000, 0.9800)"
@ s3 legend "\xD\f{}H \xl\f{} to (1.0000, 1.0000)"
@ s4 legend "pV (kJ/mol)"
0.0000 -30.652721 -425.07281 8.5014482 0.0000000 1.6549610
0.1000 -47.014614 -6562.4468 131.24881 0.0000000 1.6555369
0.2000 43.812706 -192491.17 3849.8198 0.0000000 1.6654193
...
...
...
1999.7000 115.17576 -4.0665294e+11 8.1330511e+09 0.0000000 1.5883621
1999.8000 -1642.2759 -5.8566267e+12 1.1713242e+11 0.0000000 1.5835983
1999.9000 3147.2195 -6.4759274e+11 1.2951842e+10 0.0000000 1.5708131
2000.0000 1253.8263 -5.8808771e+16 1.1761743e+15 0.0000000 1.5543262

dH/d vdw-lambda is tremendous which means that soft-core vdw must be used.

And one more question for specialists.
In pdf and online manuals I can't understand phrase about " sc-coul ":
"it is only taken into account when lambda states are used, not with  couple-lambda0 /  couple-lambda1 "

But it is impossible to establist lambda-path (which is written in mdp-file as zero-based vector) without indication of it's initial and final states given by couple-lambda0/1.
And where is the equation describing  sc-coul similar to 4.136-4.138 about sc-vdw on page 98?