Behaviour of the Eu3+ D-5(0) -> F-7(0) transition in CaMoO4 powellite type ceramics under Ar and Pb ions implantation

In this work, the Eu3+5D0 → 7F0 transition is used as a structural probe to follow the Eu3+ environment modification in powellite CaMoO4 under irradiation or when its composition is varying. Six ceramics with compositions ranging from Ca0.99Eu0.01MoO4 to Ca0.76Sr0.1Na0.07 Eu0.01La0.02Nd0.02Pr0.02 MoO4 were synthesized and each composition has a specific Eu3+ luminescence signal. The 5D0 → 7F0 transition appeared to be a very sensitive structural probe. Even if there is only one structural site in powellite for europium, the Eu3+5D0 level position changes with the modification of the Eu3+ cationic neighbours. Low 5D0 values are observed for environments containing trivalent rare earth elements when high 5D0 values are observed for Na+ rich environments. Under 8 MeV Ar ions irradiation, the Eu3+5D0 → 7F0 transition is not really affected. Under 108 MeV Pb ions irradiation there is an homogenization of the Eu3+5D0 → 7F0 transition from the different irradiated samples revealing a reorganization of the crystalline structure. (authors)