BRA_cog.itp

;;;;;; 4-BROMOANISOLE
;
; Note(s):
;   For minimizations, you may use define=-DFLEXIBLE to use a stiff-bond version of the topology that is more amenable to minimization.
;

[ moleculetype ]
; molname            nrexcl
  BRA             1

[ atoms ]
; nr    type    resnr   residue atom    cgnr    charge  mass
  1     SN2a    1       BRA     O1      1       0       54
  2     TC5     1       BRA     R2      2       0       36
  3     TC5     1       BRA     R3      3       0       36
  4     TX2     1       BRA     X4      4       0       36

[bonds]
#ifndef FLEXIBLE
[constraints]
#endif
; i     j       funct   length  
  1     2       1       0.315 1000000 ; cog  
  1     3       1       0.315 1000000 ; cog  
  2  	3	1	0.265 1000000 ; cog
  2	4	1	0.330 1000000 ; cog
  3	4	1	0.330 1000000 ; cog

[ dihedrals ]
; Keeping it flat using improper
; i     j       k       l       func    angle   strength
  1     2       3       4    	2       180     250

[ exclusions ]
; i     j       k       l
  1     4