[gmx-users] Why charge parameter of cations like Cu2+, Zn2+ in GROMOS 54a7 force field in GROMACS equals to zero?

[ABEL Stephane]

Hi 

All the the values in the charge column  in the ffnonbonded.itp are not used by GROMACS and remain present  for history reasons (and probably for compatibility with older GROMACS versions). The charges for each residue/molecules are now in the rtp. 

Best

Stéphane

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Hi all,
I am trying to modify the original GROMOS 54a7 force field files implemented in GROMACS to add parameters of some new cations. But when I checked the ffnonbonded.itp, I found that the charge parameter of CU2+, Zn2+ equals to zero. Why? What does it mean? How GROMOS 54a7 force field calculate the electrostatic interaction? If I want to add some new ions, what should I do?
Thans in advance,
Chenlin

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Chenlin Lu

Department of Chemical Engineering,

Tsinghua University, Beijing, 100084

Tel: 86-13120180517

Email: lucl17 at mails.tsinghua.edu.cn



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