[gmx-users] Result difference between Gromacs and other pakages, is it a bugs??(oplsaa)

[PeiQuan Chen]

Dear gmx-users:
  I have made a test between gromacs and tinker(hyperchem) pakages.
I have build a CH4 molecule. And use gromacs and tinker(hyperchem) pakages to do em with oplsaa force field.
And I get different energic results between gromacs and other pakages.

The Energic result of gromacs is:

   Energies (kJ/mol)
           Bond          Angle        LJ (SR)   Coulomb (SR)      Potential
    1.08454e-01    7.23328e-01    0.00000e+00    0.00000e+00    8.31783e-01
    Kinetic En.   Total Energy    Temperature Pressure (bar)
    0.00000e+00    0.00000e+00    0.00000e+00    0.00000e+00

The Tinker and hyperchem result is:

   Energy=0.168456 (Kcal/mol)
Bond=0   Angle=0.168456   Dihedral=0 Vdw=0   Electrostatic=0.

   We can translate the tinker and hyperchem result to kJ/mol form, But the result is also different.

Can anybody give me a hints? Why ? Is is a bugs in gromacs with oplsaa force field.

  Thank you in advance!


Sincerely yours
---- 
PeiQuan Chen
________________________________________________________________________
PeiQuan Chen 	Department of Chemistry, Nankai University
WeiJin Road 94, TianJin, 300071, P.R.China
phone:	(86)2223506728		Mobile Phone: (+86)13920675030
gromacs at 163.com	
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