Regarding basics of sorption module

hi,

i have entered  input pressure range for getting adsorption isotherm. in output file adsorption isotherm was in terms of fugacity and avg loading. so for a  gas does not follow ideal gas law,  under such condition we have to enter pressure / fugacity range?.

Do and Ro in Dreding forcefield parameter are same as Epsilon (ε) and sigma σ of LJ parameter ? if they are not same then is their any relation between them?