Question

the lattice vibrations with accoustical mode is caused by a) light energy b) mechanical energy c) sound energy d) all the above ​

Answer 1

Answer:

b) Mechanical energy

Explanation:

Lattice vibrations give the key to many temperature dependent properties of solids. If we know the quantum mechanical energy eigenvalues of these vibrations, we can easily model thermodynamic quantities such as the Gibbs energy and the heat capacity. If we also know the eigenfunctions corresponding to the eigenvalues, we can calculate, e.g. the vibrational displacements of the atoms and connect that to properties such as the electrical resistivity. In applications to materials science the temperature is often so high that a classical description agrees very well with the more fundamental quantum mechanical approach. We therefore start with a brief comparison of these two descriptions.