Molecular excitions and electron-hole processes in K₂SO₄and CaSO₄

Fast intrinsic emission with the participation of oxyanion and cation excitations in metal sulphates

“…A weak signal at lower energies of exciting photons testifies to the fact that a total elimination of inertial components of intrinsic emissions is impossible. In sulphates, the value of the energy gap is about E g = 9 eV [5] and the width of a valence band E v is more than 7 eV (see Fig. 1).…”

“…This emission is also known as Auger-free or core-valence luminescence. The present study is devoted to the fast emissions that can be detected in metal sulphates in addition to IBL and crossluminescence.Several bands of fast (τ < 2 ns) emission have been observed in K 2 SO 4 under irradiation by single nanosecond electron pulses [5]. The threshold exciting photon energy of 15 eV has been detected in the excitation spectra for the most intense emission bands at 5.8 and 3.8 eV.…”

“…The threshold exciting photon energy of 15 eV has been detected in the excitation spectra for the most intense emission bands at 5.8 and 3.8 eV. Taking into account the band structure calculations of K 2 SO 4 [6], these fast emissions have been ascribed to the electron transitions between subbands of a splitted valence band [5]. The investigation of the nature of fast emissions and the conditions of their excitation in various metal sulphates has much potential for yielding important information about the structure of a valence band.…”

Low-temperature investigation of electronic excitations in wide-gap materials doped with RE3+ or Cr3+ ions

“…Однако, детальное исследование процессов передачи энергии центрам люминесценции при возбуждении фосфора фотонами с энергией 5-40 эВ или электронами 5-10 кэВ в области температур 6-420 К выявило наличие нескольких сложных механизмов возбуждения примесных ионов Tb 3+ в CaSO 4 :Tb 3+ ,Na + и необходимость дальнейшего изучения возможности получения η >1 [16]. Кроме того, для прикладных задач актуальным является и продолжение исследования радиационной стойкости монокристаллов, а также имеющих большую активную поверхность порошков и керамик [17,18].…”

Electron–hole and excitonic processes in CaSO4 doped with Gd3+, Tb3+ and Dy3+ luminescent ions

“…Phosphors based on CaSO 4 are successfully used as highsensitive dosimetric materials at the detection of VUV radiation, X-and g-rays [1][2][3][4]. They are under thorough investigation with the purpose to find wide-gap spectral transformers of luminescence with quantum yield QY41 at the excitation by Xe-discharge resonant emission (8.44 eV) [4][5][6][7].…”