Some fractional parentage coefficients for R5and their application to T⊗(ϵ + τ2) Jahn-Teller systems such as F and F+centres

Fractional parentage for R 5 to R 3 are given for angular momentum states up to I=6. They are used for finding solutions of the T(X)( epsilon + tau 2 ) Jahn-Teller problem in the special case of equal coupling, with and without spin-orbit coupling. A series of theoretical bandshapes is given. Theory and experiment are compared for the stress dichroism and magnetic dichroism in adsorption (good agreement) and for the luminescence bandshape (qualitative agreement only) of the F + centre in CaO. The absorption bandshapes for F centres in the caesium halides are also compared with this model, and are quite well accounted for.