Nevertheless, other equations may provide better results and several theoretical and experimental studies show that the Murnaghan equation is unsatisfactory for many problems. Thus, to the extent that the ratio V / V 0 becomes very low, the theory predicts that K ′ goes to 5/3, which is the Thomas–Fermi limit. However, in the Murnaghan equation, K ′ is constant and set to its initial value. In particular, the value K ′ 0 = 5/3 becomes inconsistent with the theory under some situations. In fact, when extrapolated, the behavior predicted by the Murnaghan equation becomes quite quickly unlikely.