HEAT CAPACITY OF PLUTONIUM METAL BELOW 420 K

The heat capacity of plutonium as a function of temperature below 300 deg K is represented by curves and leastsquared equations for specimens of different purities and isotopic contents. Values of the electronic contribution coefficient, the Debye characteristic temperature, and energy density of states are reported, together with entropy and enthalpy at 1.9 to 298 deg K, and at 420 deg K. A figure showing the heat capacity behavior at 355 deg K to 420 deg K is also given. Anomalies in the heat-capacity curves are discussed, evidence from other types of experiments is presented to confirm their existence and significance, and possible explanations for them are considered. (auth)