Classical theory of thermal radiation from a solid

Area of Science:

• Solid-state physics
• Classical electromagnetism
• Statistical mechanics

Background:

• Solids at finite temperatures are modeled as ensembles of atoms.
• Atomic motion within lattice sites is governed by isotropic harmonic potentials.

Purpose of the Study:

• To model thermal radiation from solids based on classical atomic motion.
• To analyze the properties and low-temperature intensity of this radiation.

Main Methods:

• Modeling a solid as an ensemble of identical atoms in harmonic potentials.
• Analyzing the motion of a single atom as a time-dependent current density.
• Formulating both atomic motion and radiation in the classical domain.

Main Results:

• An atom's motion is equivalent to a time-dependent current density, enabling electromagnetic radiation emission.
• The collective radiation from all atoms constitutes the solid's thermal radiation.
• The general expression for thermal radiation is derived and its properties discussed.

Conclusions:

• Atomic motion in solids is a source of classical electromagnetic radiation.
• The derived model explains thermal radiation as a consequence of atomic current densities.
• The study provides a classical framework for understanding thermal radiation from solids, with specific calculations for low temperatures.