The Role of Symmetry in Mossbauer Relaxation Spectra

A perturbation procedure for dealing with the relaxation operator for a Mossbauer atom under-going electronic transitions is presented. When the restrictions imposed by the symmetry are also taken into account, it is found that one can greatly reduce the complexity of the computations. For example in the case of YbS+ in YES using the present theory the problem of deriving the line shape of the Massbauer spectrum is reduced to that of inverting a 40 x 40matrix and not a 80 x 80 matrix as in previous theories. Nous prhsentons une mbthode de perturbation pour traiter l’opbrateur de relaxation pour un atome Mossbauer accomplissant des transitions BlBctroniques. Si nous consid6rons les restrictions imposbes par la symBtrie, on trouve que la complexit6 des calculs est beaucoup rhduite. Pour ex-emple si nous appliquons cette thhrie au cas de Yba+ dans YES le problBme de dkterminer l