Multiphonon Processes of the 4T1g(I) Absorption in RbMnF3

Abstract
The one‐phonon spectrum K1(ω) is calculated from the 4T1g(I) absorption in RbMnF3, using the method of generating function. In the temperature range of T ≦ 35K the coupling strength S(T) obtained with K1(ω) is in good agreement with directly measured values. S (T) is then used to derive the contribution of hot band processes to the intensity of exciton—magnon transitions at temperatures T > 35 K. We conclude from the temperature variation of the line width of the magnetic dipole transitions that exciton—magnon processes dominate when the exciton decays.