Quenching of electronically excited N2 molecules and Tb3+/Eu3+ ions by polyatomic sulfur‐containing gases upon triboluminescence of inorganic lanthanide salts

The triboluminescence of Eu₂(SO₄)₃·8H₂O and Tb₂(SO₄)₃·8H₂O crystals in an atmosphere of sulfur dioxide (SO₂) or sulfur hexafluoride (SF₆) was studied. Quenching of the gaseous (emitter N₂) and solid‐state (emitter Ln³⁺) components of the triboluminescence (TL) emission spectrum was seen when compared with the TL spectra of the crystals in air. One reason for the quenching is a reduction in the effective charge both on the crystal surface and in micro‐cracks under an SO₂ or SF₆ atmosphere, leading to a decrease in the probability of electrical breakdown and a reduction in electric field strength responsible for the electroluminescence excitation of lanthanide ions in TL. In an SO₂ atmosphere, there is an additional mode of quenching, as confirmed by quenching of the crystal photoluminescence (emitter Ln³⁺). It is supposed that this quenching is due to an exchange of energy on electronic excitation of the lanthanide ions to the vibrational sublevels of the SO₂ molecules adsorbed on the crystal surface. Another additional channel of TL quenching originates from non‐radiative transfer of excitation energy during collisions between the *N₂ and SO₂ molecules in the gaseous phase.