A Possible Cause of Some Unidentified Interstellar Absorption Bands: Crystal-Field Absorption Bands due to Fe^{3+}

1970 ◽  
Vol 161 ◽  
pp. 1157 ◽  
Author(s):  
Donald R. Huffman
Keyword(s):  
Crystal Field ◽  
Absorption Bands ◽  
Interstellar Absorption ◽  
Possible Cause

Origin of the Diffuse Interstellar Absorption Bands

Nature ◽  
1968 ◽  
Vol 218 (5137) ◽  
pp. 153-153 ◽  
Author(s):  
W. W. DULEY
Keyword(s):  
Absorption Bands ◽  
Interstellar Absorption

scholarly journals Optical and Chemical Studies on Simulated Interstellar Grain Materials

1973 ◽  
Vol 52 ◽  
pp. 327-333
Author(s):  
J. D. McCullough ◽  
G. R. Floyd ◽  
R. H. Prince ◽  
W. W. Duley
Keyword(s):  
Wavelength Range ◽  
Absorption Bands ◽  
Interstellar Absorption ◽  
Interstellar Grains ◽  
Chemical Studies ◽  
Radiation Induced ◽  
Absorption Features ◽  
Important Constituent

The possibility that many different diffuse interstellar absorption features may be produced by the same type of absorbing atom in different hydrocarbon matrices on interstellar grains has been examined experimentally. The present study shows that absorption bands due to Na atoms in various hydrocarbon matrices can occur within the wavelength range 5400–5800 Å. A study of the molecules generated from the radiation-induced polymerization of C2H2 at 55 K is also reported. It is shown that C6H6 is an abundant product of this polymerization and may therefore be an important constituent of interstellar grains.

Detection of two interstellar absorption bands coincident with spectral features of C60+

Nature ◽  
1994 ◽  
Vol 369 (6478) ◽  
pp. 296-298 ◽  
Author(s):  
B. H. Foing ◽  
P. Ehrenfreund
Keyword(s):  
Spectral Features ◽  
Absorption Bands ◽  
Interstellar Absorption

Interpretation of the optical absorption spectrum of Ni-substituted lizardites

Clay Minerals ◽  
1984 ◽  
Vol 19 (1) ◽  
pp. 107-111 ◽  
Author(s):  
A. Julg ◽  
O. Julg
Keyword(s):  
Absorption Spectrum ◽  
Optical Absorption ◽  
Crystal Field ◽  
Optical Absorption Spectrum ◽  
Octahedral Site ◽  
Tetrahedral Site ◽  
Absorption Bands ◽  
The Mean

The spectrum of Ni-substituted lizardite, (Mg,Ni)3Si2O5(OH)4, has been discussed by many authors, who have successively given contradictory interpretations concerning the symmetry of the Ni-sites. Lakshman & Reddy (1973) affirmed that in garnierites Ni is in a tetrahedral site. Faye (1974) rejected this conclusion and showed that Ni2+ occupies an octahedral site. However, the Ni … O distance of 2·01 Å which he deduced from the intensity of the crystal field is unacceptable. Recently, using a completely different approach to the interpretation of the spectrum, Cervelle & Maquet (1982) claimed that Ni2+ occupies a six-coordinated site of C3v symmetry, and concluded that the mean Ni … O distance is 2·06 Å.The aim of this note is to show that it is possible to interpret the spectrum of Ni-lizardite as arising from a predominantly octahedral field with a weak C2v component which provokes a small increase in width of the absorption bands.

Diffuse interstellar absorption bands

2009 ◽  
Vol 52 (4) ◽  
pp. 489-501 ◽  
Author(s):  
FuYuan Xiang ◽  
ShunLin Liang ◽  
AiGen Li
Keyword(s):  
Absorption Bands ◽  
Interstellar Absorption

scholarly journals Absorption and Radiation Transitions in Mn2+(3d5) Configuration of Mn-Doped ZnS Nanoparticles Synthesized by a Hydrothermal Method

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Bui Hong Van ◽  
Pham Van Ben ◽  
Tran Minh Thi ◽  
Hoang Nam Nhat
Keyword(s):  
Hydrothermal Method ◽  
Crystal Field ◽  
Excited States ◽  
Average Particle Size ◽  
Average Particle ◽  
Zns Nanoparticles ◽  
Absorption Bands ◽  
Yellow Orange ◽  
Mn Content ◽  
Mn Doped

The Mn-doped ZnS nanoparticles with Mn content of 0–15 mol% were synthesized by a hydrothermal method from the solutions Zn(CH3COO)2 0.1 M, Mn(CH3COO)2 0.01 M, and Na2S2O3 0.1 M at 220°C for 15 h. These nanoparticles presented the cubic structure with average particle size about 16 nm. The yellow-orange photoluminescence (PL) band at 586 nm was attributed to the radiation transition of the electrons in 3d5 unfilled shell of Mn2+ ions [4T1(4G)-6A1(6S)] in ZnS matrix. The photoluminescence excitation (PLE) spectra monitored at the yellow-orange band, the absorption spectra also showed the near band edge absorption of 336–349 nm and the characteristic absorption bands of Mn2+(3d5) ions at 392, 430, 463, 468, 492, and 530 nm. These bands should be attributed to the absorption transitions of 3d5 electrons from the ground state 6A1(6S) to the excited states 4E(4D), 4T2(4D), 4A1(4G)-4E(4G), 4T2(4G), and 4T1(4G) of Mn2+ ions. The intensity of PL band and absorption bands of Mn2+(3d5) ions also increased with the Mn content from 0.1 to 9 mol%, but their peak positions were almost unchanged. The PLE spectra showed clearly the energy level splitting of Mn2+ ions in ZnS crystal field and allowed for the calculation of the splitting width between the excited states 4A1(4G), 4E(4G) about of 229 cm−1 (28.6 meV), and the Racah parameters B=559 cm−1, C=3202 cm−1  (γ=C/B=5.7), and the crystal field strength Dq=568 cm−1. The PL spectra with different excitation wavelengths corresponding to absorption transition bands of the PLE spectra allow for the discussion of the indirect and direct excitation mechanisms of Mn2+(3d5) ions in the ZnS crystal.

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