Mechanisms of photochemical reactions in solution. LXV. Quenching of excited singlet states of electron-rich aromatic compounds by methyl chloroacetate

1970 ◽  
Vol 92 (23) ◽  
pp. 6991-6993 ◽  
Author(s):  
George S. Hammond ◽  
M. T. McCall ◽  
Osamu. Yonemitsu ◽  
Bernhard. Witkop
Keyword(s):  
Aromatic Compounds ◽  
Photochemical Reactions ◽  
Excited Singlet ◽  
Singlet States ◽  
Excited Singlet States ◽  
Methyl Chloroacetate

Photochemical Reactions of Primary Aromatic Amines with Chloromethanes in Solution. I. Spectrochemical Studies

1989 ◽  
Vol 44 (12) ◽  
pp. 1585-1588 ◽  
Author(s):  
Wojciech Boszczyk ◽  
Tadeusz Latowski
Keyword(s):  
Hydrogen Chloride ◽  
Stability Constants ◽  
Aromatic Amines ◽  
Photochemical Reactions ◽  
Quantum Yields ◽  
Excited Singlet ◽  
Singlet States ◽  
Primary Aromatic Amines ◽  
Excited Singlet States ◽  
Induced Reaction

Interactions were studied of aniline, 4-methoxyaniline and 4-ethoxyaniline with tetrachloromethane, chloroform and dichloromethane in their ground and first excited singlet states. Stability constants of the complexes of these amines with the chloromethanes in cyclohexane were determined as well as their quantum yields of fluorescence in this solvent. The quenching of fluorescence of aniline and its derivatives by the chloromethanes was ascertained and characterized. Quantum yields of the formation of hydrogen chloride, ψΗCl, were measured during photochemically induced reaction of the amines in tetrachloromethane, chloroform and dichloromethane.

Quasiparticle Excitations in Polyenes and Polyacetylene

1987 ◽  
Vol 109 ◽  
Author(s):  
Paul Tavan ◽  
Klaus Schulten
Keyword(s):  
Dispersion Relations ◽  
Excited Singlet ◽  
Quasi Particle ◽  
Double Excitation ◽  
Singlet States ◽  
Excited Singlet States ◽  
Electron Excitations ◽  
Quasiparticle Excitations

ABSTRACTWe apply the Pariser-Parr-Pople Hamiltonian to study many-electron excitations in polyenes and polyacetylene. The excited singlet states of polyenes, calculated by a multireference double excitation expansion, are classified as quasi-particle excitations, namely as triplet-triplet magnons and particle-hole excitons. From finite polyene spectra we derive approximate dispersion relations for these quasi-particles in the infinite polyene, i.e. polyacetylene.

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