THE NATURE OF THE SPECIES RESPONSIBLE FOR THE LONG WAVE LENGTH ABSORPTION BAND IN ACIDIC SOLUTIONS OF OLEFINS

1960 ◽  
Vol 64 (3) ◽  
pp. 382-383 ◽  
Author(s):  
Harry P. Leptin ◽  
W. Keith Hall

1973 ◽  
Vol 28 (1) ◽  
pp. 109-116
Author(s):  
P. Kröning

On concentrating liquid solutions of pyrene-3-aldehyde a fluorescence of long wave length appears with increasing intensity. It reminds of the excimer fluorescence of pyrene but behaves differently in some respects. It shows a distinct dependence on solvent and excitation wave length: Whereas it may be observed with high intensity in an unpolar solvent such as n-heptane, it is completely suppressed in the strongly polar acetic acid. When it is excited in the weak long wave length part of the first absorption band, the quantum yield is higher than with excitation at shorter wave lengths. In hydrogen free liquid solvents the fluorescence also could be detected as a delayed emission. It is assumed that weakly bound dimers are present already in the ground state of the aldehyde, these being directly excited to the excimer state.



Band spectra due to the oxides of many elements are well known, but as yet little is known about the spectra of the sulphides of the same elements. Especially is this true of the sulphides of the metals, for up to the present only one, germanium sulphide, has been reported, A search for the absorption band spectra of the sulphides of the related elements, tin and lead, resulted in the discovery of two very extensive spectra, the first lying in the region λ 2600-λ 4500 and the second in the region λ 3100- λ 8000. A general description of these spectra has already been published. Both consist of overlapping progressions of bands degraded to the red. Raising the temperature of the absorbing vapour causes bands at the long wave-length ends of the spectra to be developed, the extent of the bands depending only on the maximum temperature used (for the same vapour-pressure). Lead sulphide bands in the region of greatest dispersion show apparently simple rotational structure. By analogy with PbO it would appear that the electronic transition is 1 ∑ ⟵ 1 ∑.



1931 ◽  
Vol 38 (11) ◽  
pp. 2077-2078 ◽  
Author(s):  
David M. Dennison ◽  
Norman Wright




1967 ◽  
Vol 6 (4) ◽  
pp. 360-362
Author(s):  
R. P. Vorob'eva ◽  
L. P. Zalukaev ◽  
E. N. Ivanova


1930 ◽  
Vol 1 (12) ◽  
pp. 749-757
Author(s):  
Carl E. Howe
Keyword(s):  
X Rays ◽  


1973 ◽  
Vol 17 (02) ◽  
pp. 61-71
Author(s):  
H. S. Chen ◽  
C. C. Mei

Exciting forces and moments due to plane incident waves on a stationary platform are studied in this paper. The platform is a vertical cylinder with a finite draft and elliptical cross section. The mathematical solution to the diffraction problem is obtained on the basis of the linearized long wave approximation. Numerical results via Mathieu functions are presented for a shiplike body with beam-to-length ratio Various draft-to-depth ratios and angles of incidence are considered. Results have been checked with the limiting case of a circular cylinder for the long-wave length range. Aside from its own practical interest, the present theory provides a basis for comparison with other approximate theories of slender-body type and serves as a prelude to the corresponding calculations for arbitrary wavelengths.



2005 ◽  
Vol 13 (14) ◽  
pp. 5192 ◽  
Author(s):  
Nian Ji ◽  
Mengkun Liu ◽  
Jihao Zhou ◽  
Zhifang Lin ◽  
S. T. Chui




2007 ◽  
Vol 4 (3) ◽  
pp. 387-392
Author(s):  
Baghdad Science Journal

The paper include studies the effect of solvent of dye doped in polymeric laser sample which manufactured in primo press way, which is used as an active (R6G) tunable dye lasers. The remarks show that, when the viscosity of the solvent (from Pure Water to Ethanol), for the same concentration and thickness of the performance polymeric sample is increased, the absorption spectrum is shifts towards the long wave length (red shift), & towards short wave length (blue shift) for fluorescence spectrum, also increased the quantum fluorescence yield. The best result we obtained for the quantum fluorescence yield is (0.882) with thickness (0.25mm) in Ethanol solvent in concentration (2*10-3mole/liter), while when we used the Pure Water as a solvent, we found that the best quantum fluorescence yield is (0.72) at the same thickness & concentration of the sample.



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