[gmx-users] Coulomb (SR) + Coulomb (LR) problem

[David van der Spoel]

On Thu, 2002-10-24 at 04:02, qiao rui wrote:
> Hello all:
> 
> 	I just read the answer by David regarding the electrostatic 
> interaction energy. It seems that Coulomb (LR) is for the fourier space 
> summation of the Ewald summation. 
> 
> 	However, in my simulations, I find that g_energy reporting that 
> all the Coulomb (LR) potential are exactly zero! I am using the following 
> parameters:
> 	coulombtype = PME 
> 	rvdw        = 1.1 
> 	rlist       =  1.1
>         rcoulomb    =  1.1
> fourierspacing      =  0.12
> pme_order           =  4
> ewald_rtol          =  1e-5
> 
> 	The net charge of my system is zero and the reported value of 
> Coulomb (SR) seems to be reasonable. So, why the Coulomb (LR) potential is 
> zero?
Do you mean the total LR is zero? That shouldn't be the case. However
that individual group contribution are zero.

> 	Thanks a lot.
> 
> 	sincerely,
> 
> 	Rui
> 
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-- 
Groeten, David.
________________________________________________________________________
Dr. David van der Spoel, 	Biomedical center, Dept. of Biochemistry
Husargatan 3, Box 576,  	75123 Uppsala, Sweden
phone:	46 18 471 4205		fax: 46 18 511 755
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://xray.bmc.uu.se/~spoel
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