Magneto-optical Study of a Charge-Transfer Band in Vanadium-Doped MgO

1973 ◽  
Vol 8 (2) ◽  
pp. 854-863 ◽  
Author(s):  
F. A. Modine
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Optical Study ◽  
A Charge

Optical Study of the Fe3+-Related Emission at 0.5 eV in InP:Fe

1992 ◽  
Vol 262 ◽  
Author(s):  
Klaus Pressel ◽  
G. Bohnert ◽  
A. Dörnen ◽  
K. Thonke
Keyword(s):  
Fourier Transform ◽  
Fine Structure ◽  
Charge Transfer ◽  
Transfer Process ◽  
Decay Time ◽  
Optical Study ◽  
Charge Transfer Process ◽  
Excitation Mechanism ◽  
Different Temperatures ◽  
A Charge

ABSTRACTThe 0.5 eV (2.5 μm 4000 cm1) emission band in InP has been studied by optical spectroscopy. By the use of Fourier-transform-infrared photoluminescence we have been able to observe at least a three-fold fine structure in the zero-phonon transitions at ∼ 4300 cm−1 which are studied at different temperatures. Based on the fine structure and the long decay time of 1.1 ms we ascribe the 0.5 eV emission to the 4T1 → 6A1 spin-flip transition of Fe3+. The excitation spectrum of this Fe3+-related emission shows a characteristic fine structure at ∼ 1.13 eV which belongs to a charge-transfer process of the type: Fe3+ + hv (1.13 eV) → [Fe2+, bound hole]. We discuss the excitation mechanism of the 0.5 eV emission by charge-transfer states and compare the results with an emission at 3057 cm1 in GaAs, which we attribute to the same Fe3+ transition (decay time: 1.9 ms).

Spectra of the 1:1 and 3:1 solid complexes of coronene-TCNQ

1977 ◽  
Vol 55 (21) ◽  
pp. 3712-3716 ◽  
Author(s):  
Kim Doan Truong ◽  
André D. Bandrauk
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Ground State ◽  
Electronic Absorption Spectra ◽  
Charge Transfer Band ◽  
Out Of Plane ◽  
The Individual ◽  
A Charge ◽  
Solid Complexes

Two new solid TCNQ complexes have been isolated, coronene–TCNQ 1:1 and 3:1. The infrared and electronic absorption spectra are presented for the two different stoichiometries. From these spectra we infer that the complexes are covalent in the ground state with a charge transfer band appearing at 730 nm. The out of plane vibrations of the individual molecules are noticeably perturbed upon complexation.

Charge transfer complexes of diquat and paraquat with halide anions

1987 ◽  
Vol 65 (10) ◽  
pp. 2425-2427 ◽  
Author(s):  
S. G. Bertolotti ◽  
J. J. Cosa ◽  
H. E. Gsponer ◽  
C. M. Previtali
Keyword(s):  
Charge Transfer ◽  
Charge Transfer Band ◽  
Association Constants ◽  
Charge Transfer Complexes ◽  
Ion Selective Electrodes ◽  
Halide Ions ◽  
Ultraviolet Spectrophotometry ◽  
A Charge ◽  
Difference Absorption ◽  
Absorption Measurements

The association of methylviologen, 1,1′-dimethyl-4,4′-bipyridynium (PQ2+), with halide and pseudo-halide ions was studied in water at 25 °C by ultraviolet spectrophotometry. A charge transfer band could be observed in the region around 300 nm. From difference absorption measurements the first association constant (K1,) was obtained as 1.7 (Cl−), 3.3 (Br−), 3.9 (I−), 0.7 (CN−), and 2.0(SCN−) M−1. Similar results were obtained for the dication, 6,7-dihydrodipyrido[1,2-a:2′,1′-c]pyrazinium (DQ2+), with first association constants 3.3 (Cl−), 4.1 (Br−) and 4.6 (I−) M−1. First and second (K2) association constants were also determined by a potentiometric technique using ion selective electrodes: K1 = 2.0 M−1; K2 = 0.4 M−1 for the system PQ2+–Cl− and K1 = 5.3 M−1; K2 = 0.3 M−1 for DQ2+Br−.

A SPECTROPHOTOMETRIC STUDY OF HEXA-, PENTA-, AND TETRA- COORDINATED HALOGENOCOPPER(II) COMPLEXES IN ACETONE – HYDROHALIC ACID MIXTURES

1966 ◽  
Vol 44 (14) ◽  
pp. 1643-1653 ◽  
Author(s):  
G. H. Faye
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Hydrobromic Acid ◽  
Charge Transfer Band ◽  
Visible Region ◽  
Spectrophotometric Study ◽  
Ligand Field ◽  
A Charge ◽  
Hydrohalic Acid

A spectrophotometric study of the Cu(II) – acetone – hydrochloric (hydrobromic) acid systems has revealed that at relatively high ratios of halide: copper there is a probable equilibrium between four-, five-, and six-coordinate halogenocopper(II) complexes. A distorted tetrahedral species is favored at the highest ratios. Ligand field bands of pseudo-octahedral monohalogenocopper(II) complexes and, in the visible region, a charge transfer band of the six-coordinate complex, [CuCl4(ac)2]2−, have been identified. The results of the present work point to the important role of the solvent in determining the geometries and absorption spectra of the complexes, a factor that seems to have been misinterpreted by some previous workers.

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