Disregarding point symmetry, we can simplify the crystal structure by the space group [1, 2], representing the thermodynamic state in equilibrium with the surroundings at given values of p and T. In this approach, the restoring forces secure stability of the lattice, where the masses at lattice points are in harmonic motion. In this case, we realize that their directional correlations in the lattice are ignored so that a possible disarrangement in the lattice can cause structural instability.
KeywordsPartition Function Normal Mode Lattice Vibration Conjugate Momentum Boltzmann Statistic
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