[gmx-users] itp file using Gromos96 parameters

[Alan Wilter Sousa da Silva]

Hi List

	I did a itp file for a particular molecule using Gromos96
parameters.  However, some angle parameters are not defined at
ffG43a1bon.itp. So by now a part of my itp file is as follow:

[ angles ]
;    ai     aj     ak  funct                          const.   ang.
      2      1      5     2 ga_0  ;  C -    C -   NR   100.0  117.0
      2      1     51     2 ga_0  ;  C -    C -   HC    90.0  124.0
      5      1     51     2 ga_0  ; NR -    C -   HC    90.0  119.0
      1      2      3     2 ga_0  ;  C -    C -    S   100.0  110.0
      1      2      6     2 ga_0  ;  C -    C -  CH2   100.0  127.0
      3      2      6     2 ga_0  ;  S -    C -  CH2   100.0  123.0
      2      3      4     2 ga_0  ;  C -    S -    C   110.0   90.0
      3      4      5     2 ga_0  ;  S -    C -   NR   100.0  115.0
      3      4     52     2 ga_0  ;  S -    C -   HC    90.0  121.0
      5      4     52     2 ga_0  ; NR -    C -   HC    90.0  124.0
      1      5      4     2 ga_0  ;  C -   NR -    C   100.0  110.0
      2      6      7     2 ga_12 ;  C -  CH2 -   OA   110.0  109.5
      6      7      8     2 ga_11 ;CH2 -   OA -    C    95.0  109.5
      7      8      9     2 ga_0  ; OA -    C -    N   120.0  112.0

where ga_0 have not been set yet.

I can figure out that if I include new ga_?? parameters in the
ffG43a1bon.itp file I could get to complete my itp drug file.

Nevertheless, would GMX understand if I explicit the parameters in the
drug itp file, like that?

[ angles ]
;    ai     aj     ak  funct  ang.  const.
      1      5      4     2  110.0   100.0
      2      6      7     2  ga_12 ;  C -  CH2 -   OA   110.0  109.5
      6      7      8     2  ga_11 ;CH2 -   OA -    C    95.0  109.5
      7      8      9     2  112.0   120.0

or I'd have change funct from 2 to 1 and so to explicit my parameters.
Would GMX still respect Gromos96 force field?

I would thank in advance any attention to my question.

Cheers,

-----------------------
Alan Wilter S. da Silva
-----------------------
 Laboratório de Física Biológica
  Instituto de Biofísica Carlos Chagas Filho
   Universidade do Brasil/UFRJ
    Rio de Janeiro, Brasil