[gmx-users] Ryckaert Bellemanm-dihedral in OPLS-AA

[Justin A. Lemkul]

sumanth kumar wrote:
> 
> 
> Dear all,
> 
> I had added RB dihedrals in ffoplsaabon.itp in the following way...
> 
>  P         O2     O2      O2       3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  CT       OS     CT     CT_2    3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  CT_2   CT      N       C         3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  N        CT_2   HC     HC      3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  CT      OS      P       O2       3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  P        OS      CT     CT_2    3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  N        CT_2   CT     OS       3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  CT      CT_2   C       O         3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  CT      CT_2   N        HC      3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
>  HC      CT_2   CT     OS      3      0.00000   0.00000   0.00000   
> 0.00000   0.00000   0.00000 ; TPO
> 
> I dunno how to fill the co-efficient values. so i left it as zero. Will 
> there be any problem if i leave those values as such?? or i shud change 
> those values basing on any criteria???

Read the primary literature for the OPLS force field(s).  There is a reason why 
one must take care in deriving accurate parameters rather than filling out a 
bunch of junk, crossing one's fingers, and hoping for good results.

-Justin

> 
> Please reply urgently.
> 
> Thanks in advance
> sumanth
> 

-- 
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Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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