Upon using the first outlined approach, the molecular model has only the two parameters of the Lennard-Jones potential ε ε and σ σ that can be used for the fitting, e.g. ε ε / k B = 120 K and σ σ = 0.34 n m can be used for argon. Upon adjusting the model parameters ε and σ to real substance properties, the Lennard-Jones potential can be used to describe simple substance (like noble gases) with good accuracy. Evidently, this approach is only a good approximation for spherical and simply dispersively interacting molecules and atoms. The direct use of the Lennard-Jones potential has the great advantage that simulation results and theories for the Lennard-Jones potential can be used directly. Hence, available results for the Lennard-Jones potential and substance can be directly scaled using the appropriate ε ε and σ σ (see reduced units). The Lennard-Jones potential parameters ε ε and σ σ can in general be fitted to any desired real substance property. In soft-matter physics, usually experimental data for the vapor–liquid phase equilibrium or the critical point are used for the parametrization; in solid-state physics, rather the compressibility, heat capacity or lattice constants are employed.