I am confused by the note of pair_lj/gromacs.doc.

Note that sigma is defined in the LJ formula as the zero-crossing distance for the potential, not as the energy minimum at 2^(1/6) sigma.

MARTINI force field says the sigma_ij represents the effective minimum distance of approach between two particles. Does this mean the sigma_ij is equal the sigma of LAMMPS?

If the parameters of MARTINI force field sigma_ij = 0.47nm, The parameters have to set to be 0.47nm/ (2)^(1/6).

What is the difference of sigma definition between LAMPPs and Gromacs refferring to pair_lj/gromacs? I am confused.