Correction of Fluorescence Spectra

1994 ◽  
Vol 48 (4) ◽  
pp. 436-447 ◽  
Author(s):  
J. W. Hofstraat ◽  
M. J. Latuhihin
Keyword(s):  
Absorption Spectra ◽  
Wavelength Range ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Excitation Spectra ◽  
Excitation Light ◽  
Radiative Processes ◽  
Sensing Applications

Several methods that can be applied to remove wavelength-dependent instrumental effects from fluorescence emission and excitation spectra have been investigated. Removal of such artifacts is necessary for the comparison of spectra that have been obtained on different instruments. Without correction, spectral line positions and relative intensities will be instrument-determined to a great extent. Furthermore, the application of adequate correction procedures provides excitation spectra which can be directly compared to absorption spectra; comparison of corrected excitation spectra and absorption spectra can be used to interpret the efficiency and pathways of radiative processes. Finally, corrected reflection spectra can be obtained, which can be directly transformed into absorption spectra and are useful for remote sensing applications. The methods that have been studied for the correction of emission spectra are the application of a standard lamp with calibrated spectral output and the use of fluorescence standards. The standards are a series of luminescent phosphors in polymer films and a solution of quinine sulfate dihydrate in perchloric acid, all provided with certified spectral emission values. For correction of excitation spectra, a quantum counter was applied. Several quantum counters were investigated. The best results were obtained for application of a mixture of the dyes basic blue and HITC, which provided good correction for the wavelength range 250 to 820 nm. No good quantum counters have been reported thus far for this (large) wavelength range. Correction for wavelength dependence of the excitation optics was realized by measurement of the excitation light intensity at the sample position and at the reference position with a Si photodiode. Correction factors for the excitation spectra were checked with a number of reference materials. Attention has also been paid to polarization-dependent effects that may occur in fluorescence spectra. The application of correction procedures was demonstrated for phytoplankton fluorescence spectra.

Fluorescence Emission Properties of the Cation of 4-Aminopyrazole(3,4-d) pyrimidine, an Adenine Analogue: Evidence for Phototautomerism

1980 ◽  
Vol 35 (11-12) ◽  
pp. 878-889 ◽  
Author(s):  
Jacek Wierzchowski ◽  
Marian Szczęśniak ◽  
David Shugar
Keyword(s):  
Ground State ◽  
Emission Band ◽  
Aqueous Media ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Wavelength Dependence ◽  
Tautomeric Equilibrium ◽  
Excitation Spectra ◽  
Tautomeric Forms ◽  
Wavelength Emission

A study has been made of the emission spectra at room temperature, in aqueous and alcoholic media, of 4-aminopyrazolo(3,4-d)pyrimidine (APP) and some of its methylated derivatives. The cationic forms APPH+, N2-methyl-APPH+ and N7-methyl-APPH+ exhibit intense fluorescence un­der these conditions, the first two exhibiting excitation spectra which differ from the absorption spectra, pointing to the existence of a tautomeric equilibrium in the ground state. From the shape of the excitation spectra, and comparisons with methylated analogues in fixed tautomeric forms, it follows that the emission of APPH+ originates exclusively from the species N(2)-H,N(7)-H+, the other forms being non-fluorescent. The proportion of the emitting species, calculated from the ex­citation wavelength dependence of the quantum yield, is in good agreement with data for the ground state. The emission spectrum of APPH+ in aqueous medium consists of two bands with λmax 360 nm and 430 nm, which exhibit identical excitation spectra, but are quenched to different extents by H3O+. The 430 nm emission band is absent in alcoholic media. A similar behaviour is exhibited by N7-methyl-APPH+, whereas the neutral form of this analogue exhibits only the 430 nm band. These results indicate that the long wavelength emission band of APPH+ originates from the rare tautomeric species N(7)-H formed in the excited state by photodissociation of the N(2)-H proton from the species N(2)-H,N(7)-H+. This is further confirmed by results obtained with the aid of the basicity method, as well as by salt efects in non-aqueous media. Consideration is given to the possibility of such processes occurring in other analogues of nucleic acid derivatives.

Lewis acid induced spectral changes of sterically hindered and unhindered meso-tetra(aryl)porphyrins: fluorescence emission spectra

2020 ◽  
Vol 44 (7) ◽  
pp. 3028-3037
Author(s):  
Aida G. Mojarrad ◽  
Saeed Zakavi
Keyword(s):  
Absorption Spectra ◽  
Lewis Acid ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Molecular Complexes ◽  
Fluorescence Emission Spectra ◽  
Spectral Changes ◽  
Sterically Hindered

Fluorescence spectra of a series of electron-rich and electron-deficient meso-tetra(aryl)porphyrins and their molecular complexes with DDQ, TCNE and BF3 were investigated and compared. In spite of the great resemblance between the absorption spectra of the molecular complexes, large differences were observed between their emission spectra.

The Synthesis and Electroluminescence Properties of 4-Benzofuranyl-1,8-Naphthalimide Derivatives

2012 ◽  
Vol 557-559 ◽  
pp. 1031-1036 ◽  
Author(s):  
Jian Xin Yang ◽  
Xiang Hui Wang
Keyword(s):  
Absorption Spectra ◽  
Fluorescence Spectra ◽  
Cycloaddition Reaction ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Maximum Brightness ◽  
Maximum Emission ◽  
Mild Conditions

A series of fluorescence compounds, 4-benzofuranyl-1,8-naphthalimides, were prepared through cycloaddition reaction from 4-ethynyl-1,8-naphthalimides and o-iodophenols which catalyzed by a Pd(PPh3)2Cl2 / CuI system under mild conditions. The intermediate material, 4-ethynyl-1,8- naphthalimide, was synthesized from 4-bromo-1,8- naphthalimide and trimethylsilyl- acetylene. The absorption and fluorescence spectra of 4-benzofuranyl-1,8- naphthalimides were studied and the quantum yields were measured. The maximum UV/vis absorption spectra were in the range of 375-400 nm and the maximum emission spectra were in the range of 470-510 nm. The electro- luminescent properties were also mensurated through a doped electroluminescent device which contains 1% 1,8-naphthalimides and 99% CBP (4,4'-N,N'-dicarbazole-biphenyl), It’s shown the maximum brightness reached 3700 cd/ m2 at 22.5V.

scholarly journals Luminescent Hybrid Materials Based on Curcumin Derivatives Embedded in Palygorskite

2018 ◽  
Vol 55 (1) ◽  
pp. 63-67
Author(s):  
Monica Florentina Raduly ◽  
Valentin Raditoiu ◽  
Alina Raditoiu ◽  
Luminita Eugenia Wagner ◽  
Viorica Amariutei ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Fluorescence Spectra ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Hydroxyl Groups ◽  
Fluorescent Properties ◽  
Fluorescence Emission Spectra ◽  
Curcumin Derivatives ◽  
Absorption Studies ◽  
Inorganic Matrix

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

Fourier Transform Fluorescence Spectrometry

1988 ◽  
Vol 42 (8) ◽  
pp. 1563-1566 ◽  
Author(s):  
B. Hlivko ◽  
H. Hong ◽  
R. R. Williams
Keyword(s):  
Fourier Transform ◽  
Fluorescence Polarization ◽  
Fluorescence Spectra ◽  
Laser Excitation ◽  
Emission Spectra ◽  
Laser Fluorescence ◽  
Fluorescence Spectrometry ◽  
Excitation Spectra ◽  
Polarization Spectra ◽  
Monochromatic Source

A variety of fluorescence spectra have been measured interferometrically, demonstrating the feasibility of Fourier Transform Fluorescence Spectrometry (FT-FS). Emission spectra have been measured with the use of a monochromatic source and an interferometer as the emission selector. Excitation spectra have been measured with the use of a multi-line laser. Fluorescence polarization spectra have also been recorded with the use of laser excitation. The analytical characteristics of working curves are discussed.

Luminescence and Optical Properties of Li2O3:Gd2O3:B2O3:Sm2O3 Glasses System

2014 ◽  
Vol 979 ◽  
pp. 479-482 ◽  
Author(s):  
Warawut Sa-Ardsin ◽  
Patarawagee Yasaka ◽  
J. Kaewkhao ◽  
K. Boonin
Keyword(s):  
Optical Properties ◽  
Absorption Spectra ◽  
Excited States ◽  
Emission Spectra ◽  
Concentration Quenching ◽  
Excitation Spectra ◽  
Quenching Effect ◽  
Air Atmosphere ◽  
Glass Matrices ◽  
Concentration Quenching Effect

The samarium-doped lithium-gadolinium borate [60Li2O:10Gd2O3:(30-x) B2O3:xSm2O3] (LGBO:Sm3+) glasses have been melted and quenched in stainless plate under an air atmosphere. Some physical and optical properties within wavelength concerned and photoluminescence of the LGBO:Sm3+glasses were measured and discussed. The density of glasses dropped until 0.10 mol% and tends to increase after that point, while molar volume of the glasses tends to increase with concentration of Sm2O3.. In absorption spectra, there are 2 obvious peaks in UV-VIS range and 6 peaks in NIR range indicating the Sm3+in glass matrices. The sharpness of a peak, in the absorption spectra, also increases with concentration of the dopant. The 7 obvious peaks in excitation spectra represent the transitions from the ground state6H5/2to various excited states. Furthermore, The emission spectra were observed under 404 nm light from the Xenon compact arc lamps, and showed the concentration quenching effect (CQE) at 1.00 mol% of Sm3+. Additional, The lifetimes showed decreasing trend with concentration of Sm2O3.. As the result, The LGBO:Sm3+glass doped with 1.00 mol% of Sm3+gives the highest result for luminescence properties.

Laser-induced fluorescence and discharge emission spectra of CrO. Rotational analysis of the A5Π–X5Π transition

1980 ◽  
Vol 58 (4) ◽  
pp. 516-533 ◽  
Author(s):  
W. H. Hocking ◽  
A. J. Merer ◽  
D. J. Milton ◽  
W. E. Jones ◽  
G. Krishnamurty
Keyword(s):  
Fluorescence Spectra ◽  
Rotational Temperature ◽  
Electronic States ◽  
Emission Spectra ◽  
Laser Induced Fluorescence ◽  
Spin Orbit Coupling ◽  
Excitation Spectra ◽  
Large Numbers ◽  
Parallel Polarization ◽  
Indirect Information

The A5Π–X5Π electronic transition of CrO, near 6000 Å, has been analysed in detail using laser-induced fluorescence and conventional discharge emission spectroscopy. The transition provides the first instance where it has been possible to analyse the rotational structures of quintet electronic states completely. Although the parallel polarization of the transition has prevented the spin–orbit coupling and Λ-doubling intervals from being observed directly, it is shown that sufficient indirect information exists in the spectrum for them to be obtained with fair precision. The excited state, A5Π, is perturbed by large numbers of other electronic states which have no intensity of their own for emission to the ground state. The analysis of the perturbed regions has been greatly facilitated by the laser-induced fluorescence spectra: the excitation spectra correspond to a rotational temperature close to room temperature (which offers a significant improvement in resolution over the discharge spectra), and the J-assignments of the perturbed lines given by the resolved fluorescence spectra are unambigious

Development of a Novel Fluorimeter Based on Superluminescent Light-Emitting Diodes and Acousto-Optic Tunable Filter and its Application in the Determination of Chlorophylls a and b

1997 ◽  
Vol 51 (11) ◽  
pp. 1603-1606 ◽  
Author(s):  
Troy A. Alexander ◽  
Guan-Hong Gao ◽  
Chieu D. Tran
Keyword(s):  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Emission Spectra ◽  
High Sensitivity ◽  
Tunable Filter ◽  
Excitation Spectra ◽  
Excitation Light ◽  
Light Emitting ◽  
Chlorophylls A And B

A novel, compact, inexpensive fluorimeter that has high sensitivity and no moving parts has been developed by using super luminescent (bright-blue) light-emitting diodes (SLEDs) and an acousto-optic tunable filter (AOTF). In this instrument, the recently developed gallium nitride SLEDs were used in a counterpropagating configuration to provide excitation light. These SLEDs provide not only high intensity (several milliwatts) but also wide spectral bandwidth in the blue region (from 370 to 570 nm). The AOTF can be placed before the sample to facilitate the measurements of excitation spectra or after the sample for the emission spectra measurements. This fluorimeter is suitable for the sensitive and general fluorescent analysis of a variety of compounds. It has been used, as an example, for the sensitive and simultaneous determination of chlorophylls a and b. Detection limits of 2.30 × 10−9 and 1.10 × 10−9 M have been achieved for chlorophyll a and chlorophyll b, respectively. Index Headings: Superluminescent light-emitting diode; Acousto-optic tunable filter; Fluorescence; Chlorophyll.

The fluorescence of diamond

1958 ◽  
Vol 243 (1234) ◽  
pp. 320-335 ◽  
Keyword(s):  
Heat Treatment ◽  
Fluorescence Spectrum ◽  
Absorption Spectra ◽  
Fluorescence Spectra ◽  
Subsequent Heat Treatment ◽  
Type I ◽  
Type Ii ◽  
No Emission ◽  
Excitation Spectra ◽  
Principal Line

The fluorescence has been recorded both photographically and photoelectrically, and the apparatus developed for each of these methods is described. The 3650 Å group of mercury lines has been found to excite fluorescence in all the type I and type II a diamonds examined, but type II b specimens have given no emission with this wavelength. The fluorescence spectra usually contain one or more ‘systems’ of lines, each system consisting of a main principal line accompanied by a banded ancillary structure. These systems are described and compared with features found in absorption spectra. Excitation spectra have been obtained for the two common fluorescence systems and are compared with absorption spectra. The effect of irradiation and of subsequent heat treatment on the fluorescence spectrum is described. Finally, the results are used to draw some conclusions about the nature of the centres responsible for the fluorescence.

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