Taking account of the second derivatives of the vibronic interaction energy in calculation of the intensity distribution in the absorption and fluorescence spectra of polyatomic molecules

1987 ◽  
Vol 47 (6) ◽  
pp. 1264-1269
Author(s):  
I. E. Rybkova ◽  
T. G. Burova ◽  
M. V. Priyutov
Keyword(s):  
Interaction Energy ◽  
Intensity Distribution ◽  
Fluorescence Spectra ◽  
Polyatomic Molecules ◽  
Vibronic Interaction ◽  
Absorption And Fluorescence Spectra ◽  
Second Derivatives ◽  
Derivatives Of

New organic luminophores on the basis of cyano- and dicyanopyridines

1986 ◽  
Vol 51 (5) ◽  
pp. 1061-1070 ◽  
Author(s):  
Štefan Marchalín ◽  
Jan Fähnrich ◽  
Milan Popl ◽  
Josef Kuthan
Keyword(s):  
Solvent Effect ◽  
Fluorescence Spectra ◽  
Spectral Characteristics ◽  
Stokes Shift ◽  
Conformational Structure ◽  
Absorption And Fluorescence Spectra ◽  
Organic Luminophores ◽  
The Relationship ◽  
Derivatives Of

Absorption and fluorescence spectra of solutions of cyanopyridine derivatives of polyphenylene type, II-VIII, were investigated. The spectral characteristics determined are interpreted in relation to the probable conformational structure of the investigated substances in the states S0 and S1. The relationship between the Stokes shift and the solvent effect on the fluorescence spectra is discussed.

Influence of Internal Heavy Atoms on the Spectroscopic Properties of 9-Acetoxy-10-Phenylanthracene Derivatives

1984 ◽  
Vol 39 (10) ◽  
pp. 952-959 ◽  
Author(s):  
Janina R. Heidt
Keyword(s):  
Mirror Symmetry ◽  
Fluorescence Spectra ◽  
Spectroscopic Properties ◽  
Quantum Yields ◽  
Absorption And Fluorescence Spectra ◽  
Fluorescence Quantum Yields ◽  
Heavy Atoms ◽  
Decay Times ◽  
Anthracene Derivatives ◽  
Derivatives Of

Abstract Absorption and fluorescence spectra, fluorescence quantum yields and decay times have been measured for new derivatives of 9-acetoxy-10-acetoxyhalogenophenylanthracene in dioxane. It is found that the strength of the absorption transition decreases with increases atomic number Z of the halogen substituent whereas the strength of the fluorescence transition is constant with the exception for the fluoro-substituted derivatives. The loss of mirror symmetry between the absorption and fluorescence spectra is more evident for the 10-(4-acetoxy-3'-halogenophenyl)anthracene derivatives than for the remaining compounds. The determined nonradiative electronic relaxation rate constant and "dark reactions" quantum yield increases with increasing Z value. These findings are explained on the basis of the spin-orbit coupling enlarged by the heavy substituent and through perturbation of the functional groups, which causes different changes of the molecular geometries in the S0 and S*1 states, respectively.

Local Temperature of Fluorescent Centres in Polymer Films Determined from Universal Kennard-Stepanov Relation between Absorption and Fluorescence Spectra

2000 ◽  
Vol 55 (3-4) ◽  
pp. 444-448
Author(s):  
A. Kawski ◽  
P. Bojarski ◽  
B. Kuklinski
Keyword(s):  
Excitation Energy ◽  
Intensity Distribution ◽  
Fluorescence Spectra ◽  
Local Heating ◽  
Excitation Wavelength ◽  
Absorption And Fluorescence Spectra ◽  
Emission Process ◽  
Rigid Polymer ◽  
Energy Excess ◽  
Overlapping Region

Based on the Kennard-Stepanov relation between the extinction coefficient and fluorescence inten-sity in their overlapping region, local temperatures T* are determined for several dyes and stilbene de-rivatives in PVA and PVC polymers. It is found that excitation energy excess for ṽexc >ṽ0-0 causes local heating in a rigid polymer, and the temperature difference ΔT= T*-T holds during the emission process. Such a behaviour results from slow geometrical relaxation in a polymer. Excitation energy excess is also evidenced by the fact that the intensity distribution in the emission band depends slightly on the excitation wavelength. This effect is stronger for higher energy excess

Substituted Derivatives of 10-Phenyl-9-Acetoxyanthracene. Absorption and emission spectra, quantum yield and lifetime of fluorescence

1975 ◽  
Vol 30 (5) ◽  
pp. 612-618 ◽  
Author(s):  
Janina Heidt ◽  
Józef Heidt ◽  
Janina Gronowska
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Fluorescence Spectra ◽  
Emission Spectra ◽  
Oscillator Strengths ◽  
Steric Effects ◽  
Absorption And Fluorescence Spectra ◽  
Mean Lifetime ◽  
The Mean ◽  
Derivatives Of

Abstract Absorption The absorption and fluorescence spectra of five substituted derivatives of 10-phenyl-9-acetoxy-anthracene were measured and the oscillator strengths of the 1A→1La1A→1Bb and 1A→1Cb electronic vibration bands were determined. Comparison of the absorption spectra of these compounds to the unsubstituted molecule (anthracene) indicate the presence of bathochromic and steric effects. The fluorescence quantum yield and the mean lifetime of the fluorescence were also measured.

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