Some Fundamental Modifications to Einstein’s Model of the Absorption and Emission of Radiation by Matter
W. A. Tiefenbrunner
In 1916, A. Einstein developed a model of the absorption and emission of radiation from which he derived M. Planck’s radiation law. He postulated light-induced (stimulated) emission, because within the framework of classical physics an oscillator can, depending on the phase difference, both extract energy from the electromagnetic field and transfer energy to it. In a non-coherent field, α = β should hold, where α denotes the kinetic constant of absorption and β that of stimulated emission. This assumption is indispensable for deriving the radiation law from his model. In this context, it is problematic that a certain degree of field coherence follows necessarily from his model, which implies that α ≠ β. Moreover, the model cannot readily be generalised to fields of arbitrary coherence. An alternative model for the absorption and emission of radiation by matter is therefore developed here. On the one hand, it is based on the assumption that, within a blackbody, quanta of different energies may recombine freely; on the other hand, it employs the “pairwise interference model of quantum theory” (PIMOQ). The alternative model of the interaction between light and matter allows the radiation law to be derived for thermal equilibrium in a non-coherent field, under which conditions, according to the model, no stimulated emissions occur. It also describes the behaviour of systems with a coherent field (interference experiment, laser). Furthermore, considerations are presented regarding the energy distribution within a blackbody and the explanatory scope of A. Einstein’s model in this respect.
•Mar 12, 2026•1 citation