[gmx-users] Re: Using Morse potentials with ENCAD force field

[Vitaly Chaban]

>
> Actually I think I am using the gromos force field. I have been using
> Christopher Stiles page as a guide to get started with using CNT
> http://cs86.com/CNSE/SWNT.htm. I realize now that all the modifications were
> made to ffgmx files.  So I believe I am using the gromos forcefield. Is the
> forcefield used defined by the parameters? I have added nonbonded parameters
> to ffgmxnb.itp as the following:
> [ nonboned_params ]
>   O    N    1 0.0069        1.4016E-05
>    O    O    1 0.0061        9.9676E-06
>    N    N    1 0.0076        1.8778E-05
>    C    O    1 0.0030        4.7908E-06
>    C    N    1 0.0033        6.5271E-06
>
> and the same for pairtypes
>  [ pairtypes ]
>    C    N    1  0.0033       6.5271E-06
>    C    O    1  0.0030       4.7908E-06
>    N    N    1  0.0076       1.8778E-05
>    O    O    1  0.0061       9.9676E-06
>    O    N    1  0.0069       1.4016E-05
>
> I have put just 200 nitrogen molecules in a 24.7nm x 24.7nm x 12.3nm box
> with a 10,10 cnt length 12.3nm.  The nitrogen molecules appear to not even
> interact with the cnt but it still flattens.  Any ideas?
>

Andy,

Hi. Sorry for my English, what do you mean saying "cnt flattens"?

Again, is everything right with your box side length. I mean if the
cnt fits in the box (the rim atoms)?


-- 
Vitaly V. Chaban
School of Chemistry
National University of Kharkiv
Svoboda sq., 4, Kharkiv 61077, Ukraine
email: chaban at univer.kharkov.ua
skype: vvchaban