[gmx-users] interaction potential parameters Between H2O And CO2

[Zhongjin He]

Dear  Justin,


Thanks for you reply. I have set up it


[ nonbond_params ] ; i j func sigma epsilon OW_ice CZ 1 0.31156 0.293002 OW_ice OZ 1 0.30297 0.532092 HW_ice CZ 1 0.28142 0.299728 HW_ice OZ 1 0.21942 0.392318


From the GROMACS manual, I find for [ nonbond_params ], func 1 means using LJ and func 2 means using Buckingham.
In my case, LJ is used. But I am a little confused that whether sigma and epsilon are directly used in [ nonbond_params ]
or 4* epsilon*sigma^6 and 4* epsilon*sigma^12 are used in [ nonbond_params ]?



Thanks!





At 2015-09-13 23:36:29, "Justin Lemkul" <jalemkul at vt.edu> wrote:
>
>
>On 9/13/15 11:26 AM, Zhongjin He wrote:
>> Dera GMX user,
>>
>>
>> I have simulated CO2 in water, using SPC/E for water, EPM2 model for CO2. I decide to use Lorentz-Berthelot mixing rule for H2O-H2O and CO2-CO2 LJ interaction parameters. But for CO2-H2O LJ interaction paramters,  I do not want to use  Lorentz-Berthelot mixing rule, instead, using the more
>> accurate LJ  papameters, which are  fitted potential of CO2–H2O  from the ab initio calculation results.
>>
>>
>> I do not know how to set up this, could Non-bonded tabulated interactions in gromacs be able to set up this kind of interacions between CO2 and H2O?
>> Thanks !
>>
>
>To override combination rule values, use a [nonbond_params] directive with the 
>pre-computed LJ parameters for each pair for which you wish to use those values.
>
>-Justin
>
>-- 
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>Justin A. Lemkul, Ph.D.
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