[gmx-users] Tabulated potentials

[Mark Abraham]

Hi,

OK that's a good start. Check also at long range, and consider using the
dispersion correction (iirc maybe it does some numerical integration of the
table?), or maybe really long cutoffs. Assuming your wrong-pressure result
is reproducible from different starting velocities, then it could also be a
property of the model, which you should investigate by looking also at
other properties, others' work, etc.

Mark


On Mon, May 25, 2015 at 10:15 AM 张正财 <zhangzhengc at mail.iggcas.ac.cn> wrote:

> Dear Mark，
>
>        I used mdrun -rerun. My table reproduced the potential and force.
>
>        Best,
>
>       Zhengcai
>
>
>
> Date: Sat, 23 May 2015 11:55:22 +0000
> From: Mark Abraham <mark.j.abraham at gmail.com>
> To: gmx-users at gromacs.org, gromacs.org_gmx-users at maillist.sys.kth.se
> Subject: Re: [gmx-users] Tabulated potentials
> Message-ID:
> <CAMNuMATLq-88bMyCdyoiySOz72smAG6UptYzCJXuaSb5_8eQaA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
>
>
> Hi,
>
> Does your table reproduce the potential and force for two methane atoms at
> different distances (use mdrun -rerun)
>
> Mark
>
> On Sat, May 23, 2015 at 1:21 PM ??? <zhangzhengc at mail.iggcas.ac.cn> wrote:
>
> > Dear all,
> >         I want to add the Morse potential (
> > U=D*[exp(a*(1-r/r0)-2*exp(a/2*(1-r/r0)] ) for nonbonded interactions
> > between CH4-CH4. So, I made three table files to correspond to the
> > interactions between H-H, C-H, and C-C, and I changed vdwtype=user
> > ,Dispcorr=no , energrps = C H , and energrps_table = C C C H H H.
> However,
> > when I used NVT ensemble to calculate the pressure of pure methane
> system,
> > I didnot get accurate pressure, actually the pressure is about 20 MPa
> > smaller than the experiment value. Could you give me some suggestions
> about
> > what is wrong with my set or what I missed in adding the table?
> > Sincerely yours,
> > Zhengcai,
> >
> >
> >
> >
> >
> >
> > --
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> ------------------------------
>
> Message: 4
> Date: Sat, 23 May 2015 11:55:22 +0000
> From: Mark Abraham <mark.j.abraham at gmail.com>
> To: gmx-users at gromacs.org, gromacs.org_gmx-users at maillist.sys.kth.se
> Subject: Re: [gmx-users] Tabulated potentials
> Message-ID:
> <CAMNuMATLq-88bMyCdyoiySOz72smAG6UptYzCJXuaSb5_8eQaA at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
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