In Yu et al., 2014, it is told that for Eu2O3, "since Eu 3+ can effectively be excited by 532 nm laser, the spectrum collected with 532 nm excitation presents strong intrinsic luminescence of Eu 3+ , which totally masks the lowwavenumber Raman bands. Based on the well investigated energy levels of Eu 3+ , the luminescence band at 2500 cm -1 can be assigned to 5 D0→