As mentioned above,  is one of the most common formulations for the thermal pressure coefficient.
Both  and  are affected by temperature changes, but the value of  and   of a solid much less sensitive to temperature change above its Debye temperature. Thus, the thermal pressure of a solid due to moderate temperature change above the Debye temperature can be approximated by assuming a constant value of  and .
On the contrary, in the paper, authors demonstrated that, at ambient pressure, the pressure predicted of Au and MgO from a constant value of   deviates from the experimental data, and the higher temperature, the more deviation. In addition, the authors suggested a thermal expansion model to replace the thermal pressure model.