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

Abstract

The triboluminescence of Eu (SO ) ·8H O and Tb (SO ) ·8H O crystals in an atmosphere of sulfur dioxide (SO ) or sulfur hexafluoride (SF ) was studied. Quenching of the gaseous (emitter N ) and solid-state (emitter Ln ) 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 SO or SF 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 SO atmosphere, there is an additional mode of quenching, as confirmed by quenching of the crystal photoluminescence (emitter Ln ). 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 SO molecules adsorbed on the crystal surface. Another additional channel of TL quenching originates from non-radiative transfer of excitation energy during collisions between the *N and SO molecules in the gaseous phase.

Mechanoluminescence of Ce/Tb inorganic salts in methane–acetylene mixtures with inert gases

“…Samples of crystalline hydrates (200–250 mg) were placed into a steel cylindrical cuvette with a quartz window at the bottom. ML was excited with a stirrer made from a four‐blade PTFE tube, which was driven by an electrical motor at 1000 rpm . Methane/acetylene and inert gases (He, Ne, Ar, Kr, Xe) as well as their mixtures were introduced upon the registration of ML spectra.…”

“…ML of a sapphire was studied under ethane, methane (CH 4 ), propane, and butane atmospheres; the authors recorded the luminescence of the CH radical, which is the product of the decomposition of CH 4 . ML of lanthanide salts was then thoroughly studied in the atmosphere of various monoatomic and polyatomic gases . The intensity of both N 2 (N 2 emission in air) and solid‐state (glow of a crystal) components in the ML spectrum under inert gas atmosphere increases; therefore, the lines of these gases are also observed in the gas component together with N 2.…”

“…The intensity of both N 2 (N 2 emission in air) and solid‐state (glow of a crystal) components in the ML spectrum under inert gas atmosphere increases; therefore, the lines of these gases are also observed in the gas component together with N 2. However, the purging of polyatomic gases (O 2 , CO 2 , SO 2 , SF 6 , and hydrocarbon gases) and addition of certain substances to the crystalline lanthanide salt hydrates quenches the ML even in the gas phase . It is also possible to register additional gas‐phase emitters in the ML spectra: the OH, OD, CH, C 2 radicals, and O atom as products of mechanochemical decomposition of the crystallization water, hydrocarbon gases, and molecular oxygen during the destruction process of the crystalline hydrates.…”

“…Nevertheless, only activating or quenching action of individual gases on the N 2 and solid‐state luminescence of lanthanide salts upon ML was studied in these works. Meanwhile, the study of ML in the gas mixtures has fundamental and applied interests as it was previously suggested for analytical purposes …”

Sonotriboluminescence of Terbium Sulphate Suspensions in N-Alkanes at Polyatomic Gases Atmosphere

“…Однако полное подавление свечения СТЛ суспензий наблюдается при напуске гексафторида серы. О подобном действии на классическую ТЛ некоторых этих многоатомных газов [5,6] сообщалось нами ранее. При переходе на высшие алканы (декан, гексадекан) можно заметить, что в спектрах СТЛ суспензий тушение свечения происходит постепенно.…”