Mechanoluminescence of terbium and cerium sulfates in a noble-gas atmosphere

Lines of Ne (3p-3s, 550–800 nm) and Xe (6p-6s, 800–1050 nm; 7p-6s, 475 nm) have been detected in the mechanoluminescence spectrum of terbium and cerium sulfate crystallohydrates. The luminescence of noble gas is observed jointly with the known bands of Ce³⁺ and Tb³⁺ ions and N*₂ lines. The lines corresponding to excited Xe⁺ ions (500–550 nm), indicative of achievement of electric-field strengths on the order of 10⁷ V/cm during mechanoluminescence, are also observed. It is established that, during mechanoluminescence of Tb₂(SO₄)₃ · 8D₂O in an argon atmosphere under a pressure of 1.3 atm, mechanochemical reactions of decomposition of crystallization water (D₂O) molecules cause luminescence of OD radicals; this luminescence is initiated by electron impact occurring during electrization and in discharges in crystals during destruction.