Generalized Einstein relations between absorption and emission spectra at thermodynamic equilibrium.

ABSTRACT: We present Einstein coefficient spectra and a detailed-balance derivation of generalized Einstein relations between them that is based on the connection between spontaneous and stimulated emission. If two broadened levels or bands overlap in energy, transitions between them need not be purely absorptive or emissive. Consequently, spontaneous emission can occur in both transition directions, and four Einstein coefficient spectra replace the three Einstein coefficients for a line. At equilibrium, the four different spectra obey five pairwise relationships and one lineshape generates all four. These relationships are independent of molecular quantum statistics and predict the Stokes' shift between forward and reverse transitions required by equilibrium with blackbody radiation. For Boltzmann

SUBMITTER: Ryu J 

PROVIDER: S-EPMC11406287 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature