Exclude the 1-4 interactions in TraPPE force field

User discussions
1

Dear all,

I am using TraPPE force field for alkane simulation in Gromacs which need to exclude all the Intramolecular 1-4 interactions explicitly. So I setup gen-pairs=no in forcefield.itp, and also remove the [ pairtypes ] sections. Is this enough to exclude all the 1-4 interactions? Or should I also setup fudgeLJ=0; fudgeQQ=0.

Many thanks & best regards

Cheng

2

Hi
I suggest to check carefull the page below to evaluate if you are implemented correctly your force field

http://manual.gromacs.org/current/reference-manual/topologies/topology-file-formats.html (in particular the sub section on the directive [default])

Also check that in the directive [moleculetype] in topol.top, you have molecule name; n(nrexcl)ex where n(nrexcl)ex = 3

Best regards
Alessandra

3

Hi Cheng,
Can you please tell me how you got the dihedral potential parameters in TraPPE force field to work in Gromacs topology file? I am using TraPPE united atom force field for cyclopentane in my simulation and I am having a hard time with setting up dihedral interactions in my topology file.

Thank you very much in advance.
Kav