if sys.argv.count("tfene") > 0:
    print(('tabulated potential from file %s' % potTabFENE.filename))
    interFENE = espressopp.interaction.FixedPairListTabulated(system, fpl)
    interFENE.setPotential(type1 = 0, type2 = 0, potential = potTabFENE)
else: