Your signs are correct. All numbers reported are for
lambda 0 -> 1 regardless of the actual direction of
the simulation.
jim
On Tue, 14 Nov 2000, Alessandra Ricca wrote:
>
>
> Dear Amber users,
>
> I have been running Gibbs for imidazole in water. I get identical
> forward and reverse F_energy values which I thought should be of opposite sign.
> I did not use the IDWIDE option to turn off the double-wide
> sampling.
> My input is the following:
>
> -------
> imidazole in h20; shake; CORC; no electrost. decoupling; dyn mod wind 1->0
> &cntrl
> irest = 0, ntx = 7,
> NSTLIM = -1, DT = 0.001,
> NTB = 2, NTP = 1, NPSCAL = 1,
> CUT = 8.0, NSNB = 25, SCEE = 1.2, IDIEL = 1, DIELC=1.0,
> NTC = 3, NTF = 3, TOL = .00001,
>
> NTPR = 10,
>
> NCORC = 1, IELPER = 0,
> ISLDYN = -2, ALMDA = 1.0,
> NSTMEQ = 1000, NSTMUL = 1000,
> DLMIN =0.1d-9, DLMAX = 0.05,
> &end
> -----------------------------------
>
> Here is the end of the output:
>
>
> nb-update: total= 162999 hbpair= 70548 pert= 4266
> NO DYNAMICALLY MODIFIED WINDOWS COLLECTED SINCE LAST REPORT
>
> NSTEP =1766860 TIME(PS) =1766.860 TEMP(K) = 314.101 PRESS = 7.054
> Etotal = -3967.66755 Kinetic = 966.22876 Potential = -4933.89631
> Bond = 0.00000 Angle = 21.45533 Dihed = 0.99531
> 1-4 VdW = 0.13262 1-4 Elec= -18.39581 Van d Waal = 757.37148
> Elect. = -5695.45525 H-bond = 0.00000 Constraint = 0.00000
> Ekcmt = 482.15438 VirT = 479.76242 Volume = 15704.68681
> Density = 0.98402
>
> Current Lambda = 0.999900
> Last F.E. update: Lambda = 0.999900 Step = 1764740 Method = F.E.P.
> Accumulated "forward" quantities (Regular)
> Lam+d_lam = 0.999900 F_energy = 1340.30551
> Accumulated "reverse" quantities (Regular)
> Lam-d_lam = 0.999900 F_energy = 1340.30551
> (Note: values are unchanged from last report)
>
>
> Also the value of the F_energy is very large for the beginning of the
> calculation. Is this normal ? The charges come from mp2/6-31G*.
> No electrostatic decoupling is used. The perturb. charges used are the
> same as the atomic charges from ab initio.
>
> thanks,
>
> Alessandra
>
----------------------------------------------------------------------------
James W. Caldwell (voice) 415-476-8603
Department of Pharmaceutical Chemistry (fax) 415-502-1411
Mail Stop 0446 (email) caldwell_at_heimdal.ucsf.edu
513 Parnassus Avenue (video) farbauti.compchem.ucsf.edu
University of California (netmeeting)
San Francisco, CA 94143-0446
----------------------------------------------------------------------------
Received on Tue Nov 14 2000 - 16:29:29 PST
