CH_PENALTY = ZERO produced by CGenFF forcefield for GULP, why?

GULP
1

Hi,

I intend to use auto produced CHARM forcefield produced by CGenFF to study Paracetamol structure utilizing GULP; however, it gives me CH_PENALTY = ZERO. I am wondering why and how to overcome this issue.

RESI 866775.o 0.000 ! param penalty= 0.000 ; charge penalty= 0.000
GROUP ! CHARGE CH_PENALTY
ATOM C1 CG2R61 0.139 ! 0.000
ATOM C7 CG2R61 0.139 ! 0.000
ATOM C9 CG2R61 0.139 ! 0.000
ATOM C11 CG2R61 0.139 ! 0.000
ATOM C2 CG2R61 -0.113 ! 0.000
ATOM C23 CG2R61 -0.113 ! 0.000
ATOM C24 CG2R61 -0.113 ! 0.000
ATOM C25 CG2R61 -0.113 ! 0.000
ATOM C26 CG2R61 -0.113 ! 0.000
ATOM C27 CG2R61 -0.113 ! 0.000
ATOM C28 CG2R61 -0.113 ! 0.000
ATOM C29 CG2R61 -0.113 ! 0.000
ATOM C3 CG2R61 -0.115 ! 0.000
ATOM C30 CG2R61 -0.115 ! 0.000
ATOM C31 CG2R61 -0.115 ! 0.000
ATOM C32 CG2R61 -0.115 ! 0.000
ATOM C33 CG2R61 -0.115 ! 0.000
ATOM C34 CG2R61 -0.115 ! 0.000
ATOM C35 CG2R61 -0.115 ! 0.000
ATOM C36 CG2R61 -0.115 ! 0.000
ATOM C4 CG2R61 0.107 ! 0.000
ATOM C37 CG2R61 0.107 ! 0.000
ATOM C38 CG2R61 0.107 ! 0.000
ATOM C39 CG2R61 0.107 ! 0.000
ATOM C40 CG2R61 0.107 ! 0.000
ATOM C41 CG2R61 0.107 ! 0.000
ATOM C42 CG2R61 0.107 ! 0.000
ATOM C43 CG2R61 0.107 ! 0.000

Thank you in advance.

2

I think you need to post this to the CHARMM community, since this is a CHARMM question, rather than GULP. From a quick internet search of CH_PENALTY, my guess (with no expertise) is that this isn’t a problem, but actually a good thing & you don’t want a charge penalty that is greater than zero. However, you should consult a CHARMM user or the manual for more definitive information.

1 Like
3

Will do that, thank you for the guiding and help. Much appreciated!