FudgeLJ in ffamber - Was: [gmx-users] Re: fudgeQQ (again ...)

Erik Lindahl lindahl at cbr.su.se
Tue Feb 13 22:02:27 CET 2007


On Feb 13, 2007, at 9:45 PM, Jones de Andrade wrote:

> Hi David.
> Ops, you are right. I missexplained, that is what I meant in the  
> question.
> Well, rewriting it to have the proper and correct question:
> Well, I don't even use the [pairtypes] section in my files. Only use
> the [pairs] one, in the way explained before. This means, so, that it
> should not have any problem, and reduce "independently" the 1 - 4 LJ
> potentials by a factor of 0.5, and 1 - 4 coulombic interations by a
> factor of 0.8333, correct?

Yes, but I'll nitpick since this can be important: the fudge factors  
specify the fraction of the interaction _remaining_ rather than the  
"reduction factor", so 0.83333 means that it is 83% of the standard  
Lennard-Jones interaction. I'm sure this is what you mean since your  
factors are smaller than unity :-)



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