Journal of Luminescence
Spectroscopic study of cooperative states of Nd3+ pair centers in fluorite-type crystals: A competition of dipole-dipole and quadrupole-quadrupole energy exchange
Yu.V. Orlovskii, E.A. Vagapova, Viktor E. Peet, Elena Vinogradova, Leonid O. Dolgov, V. Boltrushko, V. Hizhnyakov