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

[David van der Spoel]

On Wed, 2003-06-11 at 10:44, PeiQuan Chen wrote:
> 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.

The gromacs minimizer is not very good. But what tolerance did you use
for minimizing?

Btw, please post only once to gmx-users (and not to me privately).
> 
>   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	
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> 
> 
> _______________________________________________
> gmx-users mailing list
> gmx-users at gromacs.org
> http://www.gromacs.org/mailman/listinfo/gmx-users
> Please don't post (un)subscribe requests to the list. Use the 
> www interface or send it to gmx-users-request at gromacs.org.
-- 
David van der Spoel <spoel at xray.bmc.uu.se>