Effect of reabsorption on the fluorescence spectra of chlorophyll-a

1984 ◽  
Vol 49 (2) ◽  
pp. 474-480 ◽  
Author(s):  
Marie Urbanová ◽  
Jan Nauš ◽  
Jan Hála ◽  
Ludvík Parma
Keyword(s):  
Fluorescence Spectrum ◽  
Chlorophyll A ◽  
Simple Formula ◽  
Fluorescence Spectra ◽  
Exciting Radiation ◽  
Experimental Arrangement ◽  
Pigment Concentrations ◽  
Strong Distortion ◽  
Qualitative Picture

Simple formula for the reabsorption correction was tested on the fluorescence spectra of thin polystyrenefoils with built-in chlorophyll-a. The spectra were studied at various pigment concentrations, wavelengths and angles of incidence of the exciting radiation. It is shown that neglecting the reabsorption effect in dependence of the experimental arrangement can lead to a strong distortion of the fluorescence spectrum. The derived formula yields a good qualitative picture of the fluorescence spectra.

CHANGES IN LEAF PIGMENTS DURING SENESCENCE AND CURING OF FLUE-CURED TOBACCO

1984 ◽  
Vol 64 (1) ◽  
pp. 229-232 ◽  
Author(s):  
WILLIAM A. COURT ◽  
JOHN G. HENDEL
Keyword(s):  
Nicotiana Tabacum ◽  
Plant Growth ◽  
Chlorophyll A ◽  
Chlorophyll B ◽  
Nicotiana Tabacum L ◽  
Pigment Concentrations ◽  
Oxygen Substitution ◽  
Β Carotene ◽  
Carotenoid Degradation

Neoxanthin, violaxanthin, lutein, β-carotene, chlorophyll a and chlorophyll b in the leaves of flue-cured tobacco (Nicotiana tabacum L.) were determined in samples collected at intervals from the middle of July through harvest. Harvested leaves were also sampled at intervals during flue curing for pigment determinations. Except where interrupted by rainfall or irrigation, pigment concentrations progressively declined during plant growth; this degradation was accelerated during flue curing. Carotenoid degradation during flue curing was proportional to the degree of oxygen substitution of the carotenoid. Chlorophyll a and chlorophyll b in cured tissue were typically less than 1% of the amounts present at harvest.Key words: Carotenoids, chlorophyll, tobacco (flue-cured), flue curing, senescence

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.

Fluorometric Properties of N-Methyltetraphenylporphine and Several Derivatives: Evaluation as Standards for Determination of Chlorophyll Concentrations

1982 ◽  
Vol 36 (4) ◽  
pp. 430-435 ◽  
Author(s):  
David K. Lavallee ◽  
Thomas J. McDonough ◽  
Lisa Cioffi
Keyword(s):  
Chlorophyll A ◽  
Organic Solvents ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Quantum Yields ◽  
Polar Organic Solvents ◽  
Solvent Systems ◽  
Nonpolar Organic ◽  
Chlorophyll Concentrations

As part of an ongoing study of the chemistry and properties of N-methylporphyrins and their metal complexes, we have observed that the excitation and emission spectra of N-methyltetraphenylporphyrin and N-methyltetra( p-sulfophenyl)porphyrin and their zinc complexes closely resemble corresponding spectra of chlorophyll a. We have characterized fluorescence spectra for these species in a variety of solvents commonly used for quantitative determination of chlorophylls. Quantum yields for the N-methylporphyrins are lower by approximately a factor of 10 than yields for chlorophyll a in such solvents as acetone, ethanol, and mixed aqueous/organic solvent systems. The yields are quite sufficient, however, for these species to be used as fluorescence standards. Solution of N-methylporphyrins are stable and the compounds can be inexpensively synthesized in high purity. The tetra( p-sulfophenyl) species are soluble in aqueous and highly polar organic solvents, whereas the tetraphenyl species are soluble in nonpolar organic solvents.

scholarly journals Derivation of the stationary fluorescence spectrum formula for molecular systems from the perspective of quantum electrodynamics

2021 ◽  
Vol 61 (2) ◽  
Author(s):  
Y. Braver ◽  
L. Valkunas ◽  
A. Gelzinis
Keyword(s):  
Fluorescence Spectrum ◽  
Quantum Electrodynamics ◽  
Fluorescence Spectra ◽  
Photon Emission ◽  
Mathematical Treatment ◽  
Matrix Formalism ◽  
Physical Content ◽  
Molecular Systems ◽  
Standard Textbook ◽  
Density Matrix Formalism

Numerical simulations of stationary fluorescence spectra of molecular systems usually rely on the relation between the photon emission rate and the system’s dipole–dipole correlation function. However, research papers usually take this relation for granted, and standard textbook expositions of the theory of fluorescence spectra also tend to leave out this important relation. In order to help researchers with less theoretical training gain a deeper understanding of the emission process, we perform a step-by-step derivation of the expression for the fluorescence spectrum, focusing on rigorous mathematical treatment and the underlying physical content. Right from the start, we employ quantum description of the electromagnetic field, which provides a clear picture of emission that goes beyond the phenomenological treatment in terms of the Einstein A coefficient. Having obtained the final expression, we discuss the relation of the latter to the present level of theory by studying a simple two-level system. From the technical perspective, the present work also aims at familiarizing the reader with the density matrix formalism and with the application of the double-sided Feynman diagrams.

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