The Fluorescence and Phosphorescence Spectra and Phosphorescence Decay Time of Harmine, Harmaline, Harmalol, Harmane, and Norharman in Aqueous Solutions and EPA at 77 K

1974 ◽  
Vol 19 (3) ◽  
pp. 10221J ◽  
Author(s):  
S. G. Hadley ◽  
A. S. Muraki ◽  
Kenneth Spitzer
Keyword(s):  
Aqueous Solutions ◽  
Decay Time ◽  
Phosphorescence Decay ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

FLUORESCENCE, DEFECT FLUORESCENCE, AND PHOSPHORESCENCE SPECTRA AT 4.2 °K OF UNDOPED AND β-METHYLNAPHTHALENE-DOPED NAPHTHALENE CRYSTALS

1966 ◽  
Vol 44 (7) ◽  
pp. 1485-1515 ◽  
Author(s):  
F. R. Lipsett ◽  
G. Macpherson
Keyword(s):  
Excitation Spectrum ◽  
Decay Time ◽  
Excitation Wavelength ◽  
Defect States ◽  
Excitation Spectra ◽  
Decay Times ◽  
Temperature Dependences ◽  
Fluorescence And Phosphorescence Spectra ◽  
Fluorescence And Phosphorescence ◽  
Phosphorescence Spectra

Fluorescence, defect fluorescence, and phosphorescence spectra were obtained at 4.2 °K from undoped crystals containing unwanted impurities and from crystals deliberately doped with β-methylnaphthalene. The doped crystals included normal and fully deuterated naphthalene and β-methylnaphthalene in all combinations. Fluorescence attributable to physical defects, analogous to that recently reported for anthracene, was found in all crystals. This fluorescence consisted of bands rather than lines, and occurred in the spectral region between fluorescence (singlet emission) and phosphorescence (triplet emission). The excitation spectrum (intensity of the fluorescence as a function of excitation wavelength) showed one of two forms depending on the fluorescence band chosen, which indicated that the defect fluorescence may be excited either directly or by energy transfer, similarly to other modes of luminescence. The decay time of the defect fluorescence was < 0.01 second, indicating that the defect states are probably disturbed naphthalene singlet states.Moderately intense phosphorescence consisting of lines was found in all of the doped crystals. Assignments of the lines could not be made because of the large number of lines present. However, probable values of the triplet 0–0 levels of normal and deuterated naphthalene and β-methylnaphthalene were deduced from the present and related experiments. The undoped crystals showed a few very weak phosphorescence lines superimposed on a weak continuum of fluorescence. Those crystals with the fewest lines were the purest, and showed a decay time of line plus continuum < 0.01 second, confirming that pure naphthalene is not phosphorescent at 4.2 °K. Phosphorescence excitation spectra, decay times, and temperature dependences were found. For the doped crystals, the decay times ranged from < 0.01 to 18 seconds and the phosphorescence intensity at 10–12 °K fell to half the value at 4.2 °K, indicating an activation energy of about 37 cm−1. The phosphorescence excitation spectrum, decay time, and temperature dependence of naphthalene-d8 doped with β-methylnaphthalene were dissimilar to those of the other doped crystals, for reasons which are not yet understood.The fluorescence spectra consisted of lines for both undoped and doped crystals. The results were tabulated and compared with those of other research workers. It was not possible, however, to assign each line, to either a particular material or a particular vibrational mode.

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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