An electron spin resonance study of vanadium and chromium and impurity ions in crystals of cadmium fluoride, lead fluoride and cadmium chloride

35 GHz electron spin resonance signals have been obtained at 77 degrees K from CdF 2 :V 3+ , CdF 2 : Cr 3+ , PbF 2 : V 2+ , CdCl 2 : V 2+ and impurity centres in CdF 2 and PbF 2 . V 3+ occupies a cubic site in CdF 2 with g=1.940+or-0.001 and 51 A=91+or-2G. Cr 3+ in CdF 2 occupies a cubic site with trigonal distortion arising from a Jahn-Teller effect or local interstitial fluoride compensation with g/sub ///=1.94+or-0.01, g perpendicular to =1.97+or-0.01 and b 2 0 =1.67 cm -1 . The impurity centres in CdF 2 and PbF 2 were associated with broad line electron spin resonance signals at g=2. V 2+ in CdCl 2 occupied a substitutional distorted octahedral site with xy magnetic plane coincident with the cleavage planes and g/sub ///=1.974+or-0.001, 51 A= 51 B=80+or-2G and b 2 0 =0.208 cm -1 .