
Show transcribed image text A simple model for phonons (solid state crystal vibrations) was proposed more than a century ago by Einstein. Within this model, each of the N atoms in the crystal are assumed to vibrate independently about its lattice position. The vibration along the x, y and z axes is assumed to be independent and to be governed by a 1D harmonic potential The latter is assumed to have the same spring constant for all atoms and in all directions. A. (3 pt) Assuming that the atoms are independent and distinguishable, write down the expression for the partition function of Einstein's crystal as a function of the vibrational harmonic frequency, ω and temperature. You can use the lecture B. (3 pt) Derive an expression for the internal energy of Einstein's crystal in terms of o and temperature. C. (3 pt) Derive an expression for the heat capacity of Einstein's crystal in terms of ω and temperature.
A simple model for phonons (solid state crystal vibrations) was proposed more than a century ago by Einstein. Within this model, each of the N atoms in the crystal are assumed to vibrate independently about its lattice position. The vibration along the x, y and z axes is assumed to be independent and to be governed by a 1D harmonic potential The latter is assumed to have the same spring constant for all atoms and in all directions. A. (3 pt) Assuming that the atoms are independent and distinguishable, write down the expression for the partition function of Einstein's crystal as a function of the vibrational harmonic frequency, ω and temperature. You can use the lecture B. (3 pt) Derive an expression for the internal energy of Einstein's crystal in terms of o and temperature. C. (3 pt) Derive an expression for the heat capacity of Einstein's crystal in terms of ω and temperature.





