ESR Study of New Eu²⁺-Complex in Additively Colored KCl: Eu Crystals

Abstract

A new ESR spectrum due to Eu²⁺ ions was found in additively colored KCl: Eu crystals as well as KOH doped KCl: Eu crystals at room temperature. The angular dependence of the new spectrum has a tetragonal symmetry around [001] axis and could be analyzed by a spin Hamiltonian
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with S=7⁄2 and I=5⁄2. The spin Hamiltonian parameters were determined as g=1.995, |b₂⁰|=1189(G), b₄⁰=−2.3(G), A₁₅₁=30.1(G) and A₁₅₃=13.5(G). Both ESR and optical absorption studies suggest that the new Eu²⁺ complex is originated from the association of the Eu²⁺ ion with an O²⁻ ion at [001] site which was produced by the decomposition of an OH⁻ ion.