Thermoluminescence, fluorescence, and optical absorption studies on single crystals of rubidium iodide doped with Eu2+

1985 ◽  
Vol 63 (4) ◽  
pp. 517-521 ◽  
Author(s):  
K. L. Tan ◽  
S. Sapru ◽  
S. B. S. Sastry
Keyword(s):  
Optical Absorption ◽  
Emission Spectra ◽  
Energy Band Diagram ◽  
Band Diagram ◽  
Fluorescence Studies ◽  
Fluorescence Measurements ◽  
Absorption Studies ◽  
Order Of Magnitude ◽  
Optical Treatment ◽  
The Eu

Thermoluminescence, optical absorption, and fluorescence studies on the RbI:Eu2+ system indicate that the Eu2+ ions act as donors on irradiation and thereby convert to the Eu3+ ions. On thermal and (or) optical treatment the electrons released are captured back. The integrated light intensity of the system is an order of magnitude higher than that of the undoped samples. Fluorescence measurements show an emission around 2.83 eV. Thermoluminescence emission spectra give two emission bands peaking around 2.48 and 2.83 eV. A tentative energy band diagram is suggested explaining these emissions. Excitation of irradiated samples with F light is used to support this model.

scholarly journals A microspectrophotometer for UV–visible absorption and fluorescence studies of protein crystals

2002 ◽  
Vol 35 (3) ◽  
pp. 319-326 ◽  
Author(s):  
Dominique Bourgeois ◽  
Xavier Vernede ◽  
Virgile Adam ◽  
Emanuela Fioravanti ◽  
Thomas Ursby
Keyword(s):  
Emission Spectra ◽  
Fluorescent Substrate ◽  
Visible Absorption ◽  
Fluorescence Studies ◽  
Endogenous Fluorophores ◽  
Physico Chemical ◽  
Absorption Studies ◽  
Potential Applications ◽  
Exogenous Fluorophores ◽  
Proper Interpretation

Absorption microspectrophotometry has been shown to be of considerable help to probe crystalline proteins containing chromophores, metal centres, or coloured substrates/co-factors. Absorption spectra contribute to the proper interpretation of crystallographic structures, especially when transient intermediate states are studied. Here it is shown that fluorescence microspectrophotometry might also be used for such purposes if endogenous fluorophores are present in the macromolecule or when exogenous fluorophores are added and either bind to the protein or reside in the solvent channels. An off-line microspectrophotometer that is able to perform low-temperature absorption and fluorescence spectroscopy on crystals mounted in cryo-loops is described. One-shot steady-state emission spectra of outstanding quality were routinely collected from several samples. In some cases, crystals with optical densities that are too low or too high for absorption studies can still be tackled with fluorescence microspectrophotometry. The technique may be used for simple controls such as checking the presence, absence or redox state of a fluorescent substrate/co-factor. Potential applications in the field of kinetic crystallography are numerous. In addition, the possibility to probe key physico-chemical parameters of the crystal, such as temperature, pH or solvent viscosity, could trigger new studies in protein dynamics.

scholarly journals Fluorescent Orthopalladated Complexes of 4-Aryliden-5(4H)-Oxazolones from the Kaede Protein: Synthesis and Characterization

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1238
Author(s):  
Eduardo Laga ◽  
David Dalmau ◽  
Sofía Arregui ◽  
Olga Crespo ◽  
Ana I. Jimenez ◽  
...  
Keyword(s):  
Intramolecular Interactions ◽  
Ortho Position ◽  
Fluorescent Properties ◽  
Ancillary Ligands ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Fluorescence Measurements ◽  
Anionic Ligands ◽  
Order Of Magnitude

The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4H)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the ortho carbon of the arylidene ring. Two different 4-((Z)-arylidene)-2-((E)-styryl)-5(4H)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring (1a OMe; 1b F), were used as starting materials. Oxazolones 1a and 1b were reacted with Pd(OAc)2 to give the corresponding dinuclear orthometalated palladium derivates 2a and 2b by regioselective C–H activation of the ortho-position of the arylidene ring. Reaction of 2a (2b) with LiCl promoted the metathesis of the bridging carboxylate by chloride ligands to afford dinuclear 3a (3b). Mononuclear complexes containing the orthopalladated oxazolone and a variety of ancillary ligands (acetylacetonate (4a, 4b), hydroxyquinolinate (5a), aminoquinoline (6a), bipyridine (7a), phenanthroline (8a)) were prepared from 3a or 3b through metathesis of anionic ligands or substitution of neutral weakly bonded ligands. All species were fully characterized and the X-ray determination of the molecular structure of 7a was carried out. This structure has strongly distorted ligands due to intramolecular interactions. Fluorescence measurements showed an increase in the quantum yield (QY) by up to one order of magnitude on comparing the free oxazolone (QY < 1%) with the palladated oxazolone (QY = 12% for 6a). This fact shows that the coordination of the oxazolone to the palladium efficiently suppresses the hula-twist deactivation pathway.

NIR and Upconversion Luminescence Properties of Nd3+ Doped in Gd2O3-CaO-SiO2-B2O3 Glass System

2014 ◽  
Vol 548-549 ◽  
pp. 124-128 ◽  
Author(s):  
S. Insiripong ◽  
S. Kaewjeang ◽  
U. Maghanemi ◽  
H.J. Kim ◽  
N. Chanthima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Concentration Quenching ◽  
Luminescence Spectra ◽  
Optical Absorption Spectra ◽  
Glass Matrices ◽  
Nir Luminescence

In this work, properties of Nd3+ in Gd2O3-CaO-SiO2-B2O3 glass systems with composition 25Gd2O3-10CaO-10SiO2-(55-x)B2O3-xNd2O3 where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol% were investigated. The optical absorption spectra show peaks at 4F3/2 (877 nm) , 4F5/2+2H9/2 (802 nm), 4F7/2+4S3/2 (743 nm), 4F9/2 (682 nm), 2H11/2 (627 nm), 2G7/2 +4G5/2 (582 nm), 4G7/2 +2K13/2 (527 nm), 4G11/2 (481 nm), 2P1/2 (427 nm) and 2L15/2 + 4D1/2 + 1I11/2+ 4D5/2+ 4D3/2 (355 nm) reflecting the Nd3+ ions in glass matrices. The densities were increased with increasing of Nd2O3 concentration. This indicates the increase of the molecular weight by the replacement of B2O3 with a heavier Nd2O3 oxide in the glass. The upconversion luminescence spectra show bands at 393 nm for all Nd2O3 concentration and the strongest intensity from 2.5 % mol of Nd2O3 was obtained. For NIR luminescence, the intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1.5 mol% and beyond 1.5 mol% the concentration quenching is observed.

Thermoluminescence and optical absorption studies of RbCl:Sr2+

1985 ◽  
Vol 10 (1-2) ◽  
pp. 93-96
Author(s):  
S.B.S. Sastry ◽  
S. Nagarajan ◽  
G. Muralidharan
Keyword(s):  
Optical Absorption ◽  
Absorption Studies

TL, EPR and Optical Absorption Studies on Natural Alexandrite Compared to Natural Chrysoberyl

2002 ◽  
Vol 100 (1) ◽  
pp. 471-474 ◽  
Author(s):  
G. M. Ferraz ◽  
S. Watanabe ◽  
S. O. Souza ◽  
R. M. F. Scalvi
Keyword(s):  
Optical Absorption ◽  
Absorption Studies

EPR and optical-absorption studies of Cu2+-doped Zn(NH2(CH2)3NHOH)2Ni(CN)4 single crystals

2006 ◽  
Vol 30 (1) ◽  
pp. 75-83 ◽  
Author(s):  
H. Paşaoĝlu ◽  
B. Karabulut ◽  
G. Kaştaş ◽  
R. Tapramaz ◽  
A. Karadaĝ
Keyword(s):  
Optical Absorption ◽  
Single Crystals ◽  
Absorption Studies
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