scholarly journals Luminescence in KI:Tl

1961 ◽  
Vol 14 (3) ◽  
pp. 368 ◽  
Author(s):  
JE Alderson ◽  
SE Williams
Keyword(s):  
Single Crystals ◽  
High Energy ◽  
Activator Concentration ◽  
Host Crystal ◽  
Absorption Bands ◽  
High Energy Side ◽  
Luminescence Efficiency ◽  
Vacuum Monochromator ◽  
Impurity Centre ◽  
Energy Side

Freshly cleaved single crystals of KI:TI containing various concentrations of Tl have been irradiated in a vacuum monochromator in the 2800-1100 A region at temper. atures between -140 and 45 �0. The relative luminescence efficiencies in the Tl absorption bands and the host crystal fundamental absorption show that energy is transferred from host crystal to impurity centre to produce luminescence at room temperatures. To the high energy side of a threshold, which appears to depend on activator concentration, the luminescence efficiency is superlinear above about 15 �0 for KI:Tl (0�0005%).

scholarly journals Origin of the satellite observed on the high energy side of Lγ2,3diagram lines

2014 ◽  
Vol 534 ◽  
pp. 012018
Author(s):  
Rajeev Trivedi ◽  
Uma Shrivastava ◽  
B D Shrivastava
Keyword(s):  
High Energy ◽  
High Energy Side ◽  
Energy Side

Effect of alkylation of ammonia on the optical band shape of solvated electrons

1982 ◽  
Vol 60 (14) ◽  
pp. 1809-1814 ◽  
Author(s):  
Fang-Yuan Jou ◽  
Gordon R. Freeman
Keyword(s):  
Optical Absorption ◽  
Temperature Coefficient ◽  
High Energy ◽  
Correlation Factor ◽  
Theoretical Treatment ◽  
Band Shape ◽  
Optical Absorption Band ◽  
High Energy Side ◽  
Half Height ◽  
Energy Side

At 200 K the width at half height, W1/2, of the e−solv optical absorption band in n-propyl amine is 2.1-fold greater than that in ammonia. Three quarters of the broadening occurs on the high energy side of the band. The energy Er at half height on the low energy side of the band is nearly the same in the amine as in ammonia, while Eb, the energy at half height on the high energy side, is 42% greater in the amine. The temperature coefficient dEAmax/dT is 1.8-fold greater in the amine than in ammonia. The larger width is consistent with there being a less uniform distribution of localization sites in the system, and the larger temperature coefficient implies that the sites are more easily disturbed by thermal agitation. A quantum statistical mechanical model, such as the one begun by Simons, is needed to extend the theoretical treatment of e−solv spectra. The correlation between optical absorption energies of e−solv and the structure of the solvent, as partially reflected in the Kirkwood correlation factor, is re-emphasized.

scholarly journals Erratum: High-energy side-peak emission of exciton-polariton condensates in high density regime

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Tomoyuki Horikiri ◽  
Makoto Yamaguchi ◽  
Kenji Kamide ◽  
Yasuhiro Matsuo ◽  
Tim Byrnes ◽  
...  
Keyword(s):  
High Energy ◽  
High Density ◽  
Side Peak ◽  
High Energy Side ◽  
Peak Emission ◽  
Density Regime ◽  
Energy Side

scholarly journals Mechanism of luminescence and efficient energy storage in Lu2SiO5 : Ce3+single crystals

2020 ◽  
Vol 23 (3) ◽  
pp. 177-185
Author(s):  
V. A. Tedzhetov ◽  
A. V. Podkopaev ◽  
A. A. Sysoev
Keyword(s):  
Single Crystals ◽  
Conduction Band ◽  
High Energy ◽  
Energy Structure ◽  
Optical Transitions ◽  
Thermally Stimulated Luminescence ◽  
Excitation Energies ◽  
Absorption Bands ◽  
Electron Traps ◽  
Extrinsic Absorption

The development of high energy physics and medicine has raised the necessity of heavy stintillating materials with a large total gamma quantum absorption cross-section, high quantum output and fast response. Cerium doped lutetium silicate Lu2SiO5 : Ce3+ (LSO) has high density, large effective atomic number and high conversion efficiency. In this work we have reported optical absorption spectroscopy and photoluminescence data for LSO single crystals grown using the modified Musatov method. The absorption spectra show the fundamental intrinsic absorption edge of Lu2SiO5 at ~200 nm and four extrinsic absorption bands of Ce3+ activator near 250—375 nm. The band gap is 6.19 to 6.29 eV depending on optical beam direction. We have confirmed that the extrinsic absorption bands correspond to optical transitions in Ce3+ activator ions localized in two crystallographically non-equivalent CeI and CeII positions. We have estimated that oscillator force for the optical transitions in Ce3+ ions. The photoluminescence spectra excited by 3.49 eV photon energy UV laser contain three bands: ~2.96 eV, ~3.13 eV (CeI) and ~2.70 eV (CeII). The energy structure of electron traps in LSO has been studied with thermally stimulated luminescence, the crystals being exposed to UV with different spectral and energy parameters. All the experimental thermally stimulated luminescence curves contain at least two peaks at 345 and 400 K with a 4 : 1 intensity ratio attributable to electron traps at 0.92—0.96 and1.12—1.18 eV. LSO exposure to high pressure mercury lamp radiation having the highest energy has for the first time showed the presence of traps at 0.88 eV. A model of the energy structure of LSO has been developed. The luminescence mechanism in the material is more complex than purely intracenter one. We show that high excitation energies may lead to ionization by the mechanism hva + Ce3+ = Ce4+ + e-. We have assumed that the storage of excitation energy involves not only Ce3+ activator but also the conduction band as well as trap states localized near the conduction band.

scholarly journals High Energy Side and Rear American Football Head Impacts Cause Obvious Performance Decrement on Video

2020 ◽  
Vol 48 (11) ◽  
pp. 2667-2677
Author(s):  
Adam J. Bartsch ◽  
Daniel Hedin ◽  
Jay Alberts ◽  
Edward C. Benzel ◽  
Jason Cruickshank ◽  
...  
Keyword(s):  
High Energy ◽  
American Football ◽  
Performance Decrement ◽  
Head Impacts ◽  
High Energy Side ◽  
Energy Side

Emission Characteristics of GaN-Based EL Device with AC Operation

2000 ◽  
Vol 639 ◽  
Author(s):  
Tohru Honda ◽  
Hideo Kawanishi
Keyword(s):  
Room Temperature ◽  
High Energy ◽  
Emission Characteristics ◽  
Emission Layer ◽  
High Energy Side ◽  
Operation Frequency ◽  
Energy Side

ABSTRACTGaN-based electroluminescence devices (ELDs) were fabricated using a GaN powder as an emission layer. The electroluminescence spectra of the GaN ELDs under AC operation were observed at room temperature. The emission characteristics of GaN-based ELDs were studied to compare the EL spectra and the cathodoluminescence (CL) spectra. It was clarified that the EL spectra were similar to the CL spectra of a GaN emission layer. The emission peaks in the EL spectra were shifted toward the high-energy side with increasing operation frequency.

Electroreflectance Spectra of InGaN/AlGaN/GaN p-n-Heterostructures

2006 ◽  
Vol 955 ◽  
Author(s):  
Alexander E. Yunovich ◽  
Lev Avakyants ◽  
Mansur Badgutdinov ◽  
Pavel Bokov ◽  
Anatoly Chervyakov ◽  
...  
Keyword(s):  
Spectral Line ◽  
Quantum Wells ◽  
Flip Chip ◽  
Refraction Index ◽  
High Energy ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
High Energy Side ◽  
Franz Keldysh Effect ◽  
Energy Side

ABSTRACTElectroreflectance (ER) spectra of InGaN/AlGaN/GaN p-n- heterostructures with multiple quantum wells (MQW) are studied. Structures with MQW InGaN/GaN were grown for blue LEDs by MOCVD technology and “flip-chip” mounted. The ER spectral maxima correspond to the high energy side of electroluminescence spectral line. The ER spectra caused by Franz-Keldysh effect are approximated by Aspnes theory. The ER spectra in a range 400 ÷ 800 nm have interference bands caused by the change of refraction index in the structure.

X-Ray LIII Absorption Edges of Bismuth Halides

1978 ◽  
Vol 33 (8) ◽  
pp. 946-950
Author(s):  
P. R . Sarode
Keyword(s):  
Absorption Edge ◽  
High Energy ◽  
Pure Metal ◽  
Partial Charge ◽  
X Ray ◽  
High Energy Side ◽  
Pure Bismuth ◽  
Energy Side ◽  
Absorption Edges

The position of the bismuth LIII absorption discontinuity has been studied in pure bismuth metal and in its halides, BiF3, BiCl3, BiBr3 and BiI3 using a focussing spectrograph of the transmission (Cauchois) type. In all these compounds the discontinuity is found to shift towards the high energy side with respect to that in the pure metal. The experimental material presented in this study convincingly shows that the position of the LIII absorption edge is determined by the partial charge of the absorbing atom and not by its valence.

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