[gmx-users] Plus / Minus sign in rtp file

[Li, Shi]

Dear Gmx users,

I have a problem with the plus and minus signs while editing the .rtp file.
In the manual, it mentioned that it refers to the previous and next
residue. But what is the rule to include this? Say i have a benzene and on
C1 and C3 both bonded with a same residue. How should I include the
plus/minus? I had many trails and each time the residues will both bonded
with the same carbon (C1), leading to a long bond in the topology.
This is an example I used in the. rtp file. Can anyone tell my why this is
wrong and what is the rule?

;Benzene

[ bonds ]
....
  C1  +CT
 -CT  C3
...
[ residue ]
...
  CT  +C3
  CT   -C1
....
....

Many thanks,
Shi