Gay-Berne - Sigma

Dear Users,

In the Gay-Berne potential, the manual defines parameter sigma can be minimum effective particle diameter (though this is not required). If the shape parameters of the particle is defined as 1.0:1.0:0.1, but the sigma is chosen to be 1.0 (the maximum of the diameter), will the interaction of the particle be similar to that of between two spherical particles? Or will the interaction of the particle be that of a aspherical particle with effective diameter between 0.1 and 1.0 (which may depend on applied pressure), when in a face-to-face configuration.

I am bit confused as the manual clearly tells “To treat the particle as a LJ sphere with sigma = D, you should normally set epsilon a = b = c = 1.0, set the pair_coeff sigma = D, and also set the 3 shape parameters for the particle to D.”


You should look at the original GB papers, but
normal procedure is to set the GB sigma to be
less (or equal) to any of the 3 shape params.

As I recall, it is conceptually the size of small particles
that are being integrated over to fill the large
aspherical particle and determine its analytic
formula. Hence you don’t the small particle
to be bigger than the large particle.