[AMBER] TI with ifsc==2

From: Kepa K. Burusco <kekoburgo.yahoo.es>
Date: Thu, 25 Jul 2013 17:24:32 +0100 (BST)


Hi everybody,

I am reading the subroutine runmd() in file runmd.f in amber11 code and I have found in the first Soft Core code in section "MAKE A FIRST DYNAMIC STEP" the next "if-statement":

if ( ifsc == 2)
    ! If this is a perturb to nothing run, scale forces and calculate dvdl
    call sc_nomix_frc(f,nr3,ener)
end if

I have been reading amber11 manual and I have found that flag ifsc (in pg. 102) has only two possible values:

 = 0 SC potentials are not used (Default)

 = 1 SC potentials are used

but nothing about ifsc = 2.

I was wondering, what does it mean "a perturb to nothing"? Is that the case when you have a solute in a solvent box and you make it dissappear according to lambda to calculate the hydration free energies?

I run a hydration free energy calculation one month ago and I just selected the ifsc=1 flag with the appropriate topology and coordinate files for the starting and ending states. Is that right?

Thank you for your help!!

Kepa K.

AMBER mailing list
Received on Thu Jul 25 2013 - 09:30:03 PDT
Custom Search