Radiation of the blackbody in the external field
  The blackbody is considered in the external general field. The additional coefficients of stimulated emission and absorption are introduced into the Einstein mechanism. Then, the generalized Planck formula is derived. The Einstein and Debye formula for the specific heat is possible to generalize. The application of the theory to the sonoluminescence, the relic radiation and solar spectrum is discussed. 
Miroslav Pardy