Absorption, fluorescence and phosphorescence spectra of the singlet and triplet states of s-tetrazine in the crystal and in mixed crystals at low temperatures

1974 ◽  
Vol 27 (3) ◽  
pp. ii
Author(s):  
R.M. Hochstrasser ◽  
D.S. King
Keyword(s):  
Low Temperatures ◽  
Mixed Crystals ◽  
Triplet States ◽  
Singlet And Triplet States ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

Zur Photolumineszenz von Benzologen des Thiophens

1985 ◽  
Vol 40 (5) ◽  
pp. 497-502 ◽  
Author(s):  
Maximilian Zander
Keyword(s):  
Energy Gap ◽  
Heavy Atom ◽  
Phosphorescence Spectrum ◽  
Quantum Yields ◽  
Triplet States ◽  
Fluorescence And Phosphorescence Spectra ◽  
Atom Effect ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra ◽  
Hydrocarbon Fragment

Fluorescence and phosphorescence spectra, fluorescence and phosphorescence quantum yields and phosphorescence lifetimes of the benzologues I -V of thiophene have been measured in ethanol at 77 K. By comparing the energies of the lowest triplet states of the molecules with those of corresponding hydrocarbons it is concluded that the sulphur atoms act like substituents and are not equivalent to aromatic double bonds. The rate of the radiationless deactivation of the lowest triplet state depends on the energy gap Δ E(T1 - S0) in accordance with the Siebrand relation. An unexpected small intraannullar heavy-atom effect of the sulphur is observed in 2,2′-bis-benzo[b]thienyl (II), a strongly fluorescing compound. As the most likely explanation it is concluded from experiments that in II the interaction between the heavy-atom and the π-MO’s of the hydrocarbon fragment (1,4-biphenylbutadiene) is much smaller compared to that in other structurally related benzologues of thiophene. External heavy-atom perturbers (AgClO4, CH3J) have a strong influence on the vibronic structure of the phosphorescence spectrum of IV.

Photochemisches Verhalten und spektroskopische Eigenschaften von Anilino-naphthalinen

1976 ◽  
Vol 31 (8) ◽  
pp. 987-989 ◽  
Author(s):  
F. Fratev ◽  
O.E. Polansky ◽  
M. Zander
Keyword(s):  
Excited State ◽  
Aromatic Amines ◽  
Ring Closure ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

AbstractFrom the fluorescence and phosphorescence spectra of several aromatic amines it is concluded that the conjugation between nitrogen and aryl groups in the excited state is restricted. With this result a sterical explanation for the lack of the expected photochemical carbazole ring closure of 1-and 2-anilino naphthalene is given.

A NOVEL GREEN LONG-LASTING PHOSPHOR Ca2ZnSi2O7:Eu2+

2011 ◽  
Vol 04 (03) ◽  
pp. 289-293 ◽  
Author(s):  
WEI ZENG ◽  
YUHUA WANG ◽  
XUHUI XU ◽  
YU GONG
Keyword(s):  
High Temperature ◽  
Zinc Vacancy ◽  
Solid State Method ◽  
Naked Eye ◽  
State Method ◽  
Relationship Of ◽  
The Relationship ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

A new green emitting long-lasting phosphor Ca2ZnSi2O7:Eu2+ has been synthesized through the high temperature solid-state method. The excitation spectrum of [Formula: see text] shows a broadband attributed to 8S7/2–4f65d1 transition of Eu2+ ions. Both of the fluorescence and phosphorescence spectra showed a broadband centered at 528 nm, corresponding the only one Ca2+ site in Ca2ZnSi2O7 . The relationship of emission wavelength and Eu–O distance is investigated. Its afterglow can be seen with the naked eye in the dark clearly for 2 h after removal of the excitation source. Oxygen vacancy [Formula: see text] and zinc vacancy [Formula: see text], two different kinds of traps are proposed and their contrary influence on afterglow is discussed.

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