PsychonautQQ said:you mean in the Einstein model the independence is a consequence of assumed harmonicity of oscillators? Or in the Debye model the collective modes are regarded as independent because of the assumed harmonicity?
The Einstein model assumes that all atoms in a solid vibrate with the same frequency, while the Debye model takes into account the different vibrational frequencies of atoms in a solid.
The Debye model is generally considered to be more accurate for describing the heat capacity of solids, especially at low temperatures.
The Einstein model does not account for anharmonicity, as it assumes that all vibrations are harmonic.
The Einstein and Debye models are both valid for solids with a well-defined lattice structure, but they may not accurately describe the heat capacity of amorphous or disordered solids.
At high temperatures, the Einstein model predicts a constant heat capacity, while the Debye model predicts that the heat capacity will approach a linear increase with temperature.