[gmx-users] Lennard Jones Parameters for Ammonia in ffoplsaa

Darrell Koskinen darrellk at ece.ubc.ca
Mon Oct 19 08:47:06 CEST 2009

I see that the Lennard Jones parameters for the N & H atoms in ammonia, 
represented by opls_127 and opls_128 in the file ffoplsaanb.itp are:

 opls_127   NT  7     14.00670    -1.020       A    3.42000e-01  7.11280e-01
 opls_128   H   1       1.00800     0.340       A    0.00000e+00  

Why are sigma and epsilon both zero for H? Are the LJ parameters for H 
embedded in the parameter for NT? If so, how were these parameters combined?



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