Recent computational work evaluated the phase stability of ${\mathrm{UCo}}_2$ and ${\mathrm{UNi}}_2$ in the C14, C15, and C36 Laves phases and reported their computationally determined phonon density of states. To corroborate these computational findings, we report the experimentally determined phonon density of states for ${\mathrm{UCo}}_2$ and ${\mathrm{UNi}}_2$ using inelastic neutron scattering at the wide angular-range chopper spectrometer at the Spallation Neutron Source at Oak Ridge National Laboratory. We found excellent agreement between experimental and computational results for ${\mathrm{UNi}}_2$ and noted that some differences were observed for ${\mathrm{UCo}}_2$. By comparing the phonon density of states of ${\mathrm{UCo}}_2$ with that of other U-bearing Laves phases, we found that ${\mathrm{UCo}}_2$ showed distinct vibrational properties. From the one-phonon density of states, we calculated the lattice contribution to the specific heat of ${\mathrm{UNi}}_2$ and ${\mathrm{UCo}}_2$. Finally, we bound the electronic contribution to the specific heat in ${\mathrm{UNi}}_2$.

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• Phonons
• Actinides
• Inelastic neutron scattering
• Specific heat measurements