[gmx-users] About Tabulated Potentials

[Zhengcai Zhang]

 Dear Justin,
Thank you for your reply. When I choose l-J form potential for the non-bonded interactions between CH4 and CH4 using the parameters from another paper, I can get system pressure (25.5Mpa) in accord with experimental value at same conditions. However, when I used tabulated potentials to add the morse form potentials, I got the pressure 5Mpa. I am confusing whether the tabulated potential works with the morse form potential.
          Best,
         Zhengcai

> 在 2015年5月22日，01:54，Justin Lemkul <jalemkul at vt.edu> 写道：
> 
> 
> 
>> On 5/21/15 8:36 AM, zhangzhengc wrote:
>> Dear all, I want to add the Morse potential for nonbonded interactions
>> between CH4 and CH4. I used three table files each contain seven columns to
>> add the H to H, H to C, and C to C Morse form interactions. I set
>> Coulombtype=user, vdwtype=user , and Dispcorr = no, and add energrps and
>> energrps_table in the mdp file. However, when I did NVT simulations, I didnot
>> get accurate pressure for my pure methane system. Actually the pressure is 20
> 
> I don't know much about tabulated potentials, but a question to get the ball rolling:
> 
> How do you define "accurate" - from some previous run?  Without tabulated potentials?  If the latter, it means your tables are wrong with respect to whatever parameters gave the "right" behavior.
> 
> -Justin
> 
>> Mpa smaller. Could you tell what is wrong with my set or what I missed in
>> adding tabulated potentials? I tested the using of tabulated potentials with
>> LJ form potential, It works very well. Look forward to your reply, Sincerely
>> yours Zhengcai,
> 
> -- 
> ==================================================
> 
> Justin A. Lemkul, Ph.D.
> Ruth L. Kirschstein NRSA Postdoctoral Fellow
> 
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> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
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