scholarly journals Low-Temperature Luminescent Studies of Emissive Guanine Substitute for the Detection of Biopolymers

2020 ◽  
Vol 65 (4) ◽  
pp. 317
Author(s):  
V. Yu. Kudrya ◽  
V. M. Yashchuk ◽  
A. P. Naumenko ◽  
Y. Mely ◽  
Ya. O. Gumenyuk
Keyword(s):  
Energy Transfer ◽  
Low Temperature ◽  
Optical Absorption ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Band Maximum ◽  
Frozen Solution ◽  
Buffer Solutions ◽  
Long Wave ◽  
Fluorescence And Phosphorescence

The optical absorption at 300 K and the fluorescence and phosphorescence at 78 K of the emissive guanine substitute, deoxythienoguanosine, (dthG) were investigated in aqueous and TRIS-HCl-buffer solutions. Two optical absorption and fluorescence centers at room temperature were attributed to two keto-enol tautomers of dthG, which confirms previously obtained results. In contrast to room temperature, only one emission band was observed at 78 K in fluorescence spectra that was close to the long-wave fluorescence band at room temperature and could be associated with the tautomer with long-wave absorption. This phenomenon can be explained by the energy transfer by excitations in a frozen solution between two types of the optical centers mentioned above. The similar conclusion is drawn for the phosphorescence: only one tautomer phosphorescence band is observed. The spectral positions of this band maximum are essentially different for aqueous and buffer solutions (∼50 nm).

Metastable Percolation Phase Formation in Lif Implanted with Alkali Ions

1981 ◽  
Vol 7 ◽  
Author(s):  
J. Davenas ◽  
P. Thevenard ◽  
C. Dupuy
Keyword(s):  
Low Temperature ◽  
Optical Absorption ◽  
Phase Formation ◽  
Room Temperature ◽  
Critical Concentration ◽  
External Perturbation ◽  
Metallic Layer ◽  
Alkali Ions ◽  
Conducting State ◽  
Equilibrium Situation

ABSTRACTThe formation of a continuous metallic layer in the doped region of LiF crystals implanted at low temperature, has been explained by the formation of bridges between next neighbouring alkali ions of the lattice around-each implanted ion. For a critical concentration of implanted ions it is possible to show using statistical arguments that conducting chains are formed by the union of these links, according to a percolation mechanism. We show that the assumption of a distribution of isolated implanted ions at low temperature is justified by the observation of their precipitation when the crystal is warmed up to room temperature. The transformation of the metallic optical absorption into the colloidal band associated with precipitates of implanted ions is correlated with the transition from a conducting state to an insulating state of the implanted layer. We show that this evolution towards an equilibrium situation may be reversed by a reirradiation, which is used as an external perturbation and that the conducting state associated with dispersed implanted ions is then once again obtained.

Some Pattern Recognition Considerations for Low-Temperature Luminescence and Room Temperature Fluorescence Spectra

1982 ◽  
Vol 36 (2) ◽  
pp. 110-116 ◽  
Author(s):  
Gene Sogliero ◽  
Delyle Eastwood ◽  
Robert Ehmer
Keyword(s):  
Pattern Recognition ◽  
Low Temperature ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Spectral Structure ◽  
Spectral Quality ◽  
Spectral Techniques ◽  
Scan Speed ◽  
Spectral Libraries

Low-temperature (77 K) luminescence (LTL) and room temperature fluorescence (RTF) spectra of polynuclear aromatic hydrocarbons with varying amounts of spectral structure are studied as a function of several instrument parameters (emission slit width, scan speed, and damping) in order to develop quantitative criteria for spectral quality and reproducibility. The purpose of this study is to assess the classification and pattern recognition capabilities for hazardous chemicals for various spectral techniques and to develop suitable spectral libraries and search routines. In order to quantitate the effect of the instrument parameters on the spectrum, a statistic (power) was used to measure spectral quality. In addition, three measures of similarity, used for assessing the agreement between two patterns (spectra), were evaluated to determine the variability that can be expected in spectra obtained under the same and different instrumental conditions. Analysis of the data confirms that the low-temperature luminescence technique produces better quality spectra than the room temperature fluorescence technique, but that room temperature fluorescence spectra are more repeatable.

Spectra Analysis of some Europium(III)/Terbium(III) Complexes

2016 ◽  
Vol 680 ◽  
pp. 558-561
Author(s):  
Wei Yang ◽  
Qiang Li ◽  
Yan Yan Zhang ◽  
Dan Yu Jiang ◽  
Jin Feng Xia
Keyword(s):  
Energy Transfer ◽  
Rare Earth ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Rare Earth Ions ◽  
Rare Earth Complexes ◽  
Spectra Analysis ◽  
Ultraviolet Spectra ◽  
Hydroxy Quinoline

a series of Eu(III)/Tb(III) complexes with а-thenoyl trifluoroacetone (HTTA), 8-hydroxy quinoline complexes were synthesized. The UV and fluorescence spectra of these complexes at room temperature were characterized. The results revealed that different energy transfer between rare earth ions and ligands.Keywords rare earth complexes, ultraviolet spectra, fluorescence spectra

Magnetic-downconversion luminescent bifunctional BaGdF5:Dy3+,Eu3+ nanospheres: energy transfer, multicolor luminescence and paramagnetic properties

RSC Advances ◽  
2016 ◽  
Vol 6 (58) ◽  
pp. 53444-53453 ◽  
Author(s):  
Hongxia Guan ◽  
Yanhua Song ◽  
Pingchuan Ma ◽  
Meiqi Chang ◽  
Jie Chen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Low Temperature ◽  
White Light ◽  
Room Temperature ◽  
Color Tunable ◽  
Paramagnetic Properties

The color-tunable and white light emissions have been obtained in Dy3+ and Eu3+ co-activated BaGdF5 phosphors by adopting different excitation wavelengths. Simultaneously, the obtained samples also exhibit paramagnetic properties at room temperature and low temperature.

Changes in the Photophysical Properties with Heavy Atoms and the Effects of Modulus for 4-Phenylphenol in Solid-Matrix Luminescence

1992 ◽  
Vol 46 (6) ◽  
pp. 988-993 ◽  
Author(s):  
Barbara B. Purdy ◽  
Robert J. Hurtubise
Keyword(s):  
Quantum Yield ◽  
Low Temperature ◽  
Young’S Modulus ◽  
Filter Paper ◽  
Room Temperature ◽  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Phosphorescence Quantum Yield ◽  
Atom Effect ◽  
Fluorescence And Phosphorescence

Fluorescence and phosphorescence quantum yields and fluorescence and phosphorescence lifetimes were obtained for 4-phenylphenol adsorbed on filter paper with either NaCl, NaBr, or Nal at 296 and 93 K. From these data several photophysical parameters were calculated and compared. In general, the photophysical data showed that the heavy-atom effect was operative, with NaI showing the greatest effect. However, NaBr at 93 K showed both the heavy-atom effect and another effect which was particular to NaBr. For 4-phenylphenol with NaI, very little increase occurred for the phosphorescence quantum yield from 296 to 93 K, which indicated that almost maximum phosphorescence quantum yield was achieved at room temperature for 4-phenylphenol with NaI present. The increase in phosphorescence lifetime for 4-phenylphenol from room temperature to low temperature was shown to be related to the increase in the Young's modulus of filter paper as the temperature was lowered. Calculated phosphorescence lifetimes at room temperature and at low temperature with equations that included Young's modulus values agreed very well with experimental lifetime values.

Radiation Damage Mechanisms In Scintillator Materials: Applications to BaF2 and CeF3

1994 ◽  
Vol 348 ◽  
Author(s):  
L. E. Halliburton ◽  
G. J. Edwards
Keyword(s):  
Low Temperature ◽  
Optical Absorption ◽  
Radiation Damage ◽  
Room Temperature ◽  
Epr Spectrum ◽  
Absorption Bands ◽  
Paramagnetic Resonance ◽  
Damage Mechanisms ◽  
Temperature Damage ◽  
F Centers

ABSTRACTResults from recent radiation damage studies in high quality BaF2 and CeF3 crystals are presented. Optical absorption and electron paramagnetic resonance (EPR) techniques are used to identify specific radiation damage mechanisms. Specific attention is given to the role of oxygen and hydrogen in the room temperature damage of BaF2. Also, Mn2+ ions are shown to change valence state in BaF2during room temperature irradiation. Numerous optical absorption bands are created in CeF3 during irradiations at low temperature. These bands are associated with electron traps (either F centers or Ce2+ ions) and they thermal anneal below room temperature. An EPR spectrum, assigned to F centers, is observed in low-temperature irradiated CeF3.

Comparison of Solution and Solid-Matrix Luminescence Parameters

1993 ◽  
Vol 47 (1) ◽  
pp. 116-122 ◽  
Author(s):  
R. J. Hurtubise ◽  
S. M. Ramasamy
Keyword(s):  
Low Temperature ◽  
Rate Constants ◽  
Room Temperature ◽  
Solid Matrix ◽  
Quantum Yields ◽  
Solid Matrices ◽  
Fluorescence And Phosphorescence

A relatively large number of comparisons have been made between solution luminescence and solid-matrix luminescence parameters for several lumiphors adsorbed on a number of solid matrices. Comparisons have been made for both room-temperature and low-temperature fluorescence and phosphorescence quantum yields, fluorescence and phosphorescence lifetimes, and a variety of photophysical rate constants. The comparisons reveal that solid-matrix luminescence can give greater fluorescence and phosphorescence quantum yields in many cases at room temperature, compared to the corresponding solution quantum yields at low temperature. The comparisons of fluorescence and phosphorescence lifetimes and the photophysical rate constants for the lumiphors adsorbed on solid matrices and in solutions reveal new insights into the differences between solid-matrix luminescence and solution luminescence.

White light-emitting, tunable color luminescence, energy transfer and paramagnetic properties of terbium and samarium doped BaGdF5 multifunctional nanomaterials

RSC Advances ◽  
2016 ◽  
Vol 6 (77) ◽  
pp. 73160-73169 ◽  
Author(s):  
Hongxia Guan ◽  
Ye Sheng ◽  
Yanhua Song ◽  
Keyan Zheng ◽  
Chengyi Xu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Low Temperature ◽  
White Light ◽  
Room Temperature ◽  
Excitation Wavelength ◽  
Light Emitting ◽  
Multifunctional Nanomaterials ◽  
Paramagnetic Properties

Multicolor luminescence of BaGdF5:Tb3+,Sm3+ nanospheres can be obtained by adjusting the excitation wavelength. The obtained phosphors also exhibit paramagnetic properties at room temperature and low temperature.

Fluorescence Spectra of Europium (III) Phthalate and Naphthalate and of Samarium (111), Europium (Ill), Terbium (III) and Dysprosium (III) Dipyridyl Complexes

1964 ◽  
Vol 19 (4) ◽  
pp. 434-439 ◽  
Author(s):  
Shyama P. Sinha ◽  
Chr. Klixbüll Jørgensen ◽  
R. Pappalardo
Keyword(s):  
Energy Transfer ◽  
Aqueous Solutions ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Line Emission ◽  
Emission Spectra ◽  
Main Constituent ◽  
Solid Samples ◽  
Methanolic Solution

The line emission spectra were measured at 300 °K and 78 °K in solid samples of europium (III) phthalate and naphthalate and in the α,α'-dipyridyl complexes Sm dip2 Cl3, 2 H2O; Eu dip2 Cl3, 2 H2O; Tb dip2(NO3)3 and Dy dip2(NO3)3, H2O. The gadolinium (III) compound Gd dip2 Cl3, 2 H2O shows a typical VAN UITERT effect of energy transfer from the main constituent to Eu (III) and Tb(III) present in the concentration range 0.01-0.1 mole %. The methanolic solution of Gd(III) does not exhibit such energy transfer, whereas Eu dip2+3 and aqueous solutions, probably of Eu phthal2- and Eu naphthal2-. fluoresce strongly at room temperature. However, the latter solution tends slowly to deposit crystalline salts.

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