Structure Of Absorption Spectra Research Articles

Direct observation of split-off exciton and phonon structures in absorption spectrum of silicon

The split-off band exciton of silicon has been observed in the absorption spectrum by using a wavelength modulation technique. The spin-orbit splitting of the valence band is determined to be 44.1 ± 0.3 meV at 1.8 °K. The structures associated with some two-phonon indirect transitions have also been observed in the absorption spectrum.

Fine Structure in the Absorption Spectrum of Alpha-MnS

Fine structures in absorption spectra of α-MnS single crystals are investigated at low temperatures. The sharp and temperature-independent band C : 6 A 1 →[ 4 A 1 , 4 E ] has five components, which can be explained in terms of covalency, descent of the crystal field symmetry and phonon-assisted transitions. In the visible and near-ultraviolet regions, five absorption bands are observed. The calculated band positions are fit for the observed bands at 4.2°K with the covalency parameter e =0.17, the Racah parameters B =808 cm -1 , C =3751 cm -1 and the crystal field strength D q =1025 cm -1 .

On the magnetic and optical behaviours of CoCs3Cl5

Abstract A discussion of the behaviour of CoCs 3 Cl 5 , a tetrahedral complex of Co 2+ is given, which consists of the assignment of fine structure in absorption spectra and explanation of e.p.r. as well as magnetic mean susceptibility and anisotropy results. The same set of values for the involved theoretical parameters has been seen to give reasonably good fit with all these experimental results. There is evidence of the change of anisotropic field parameters with temperature, though the calculation of this has not been attempted for uniqueness of fittings. There occur a reduction in Racah parameter B from its free ion value, and an anisotropic orbital reduction factor, which indicate an appreciable anisotropic covalency overlap between the d-charge clouds of Co 2+ with the surrounding s- and p- charge clouds of chlorine.

The fine structure of X-ray absorption K-spectra of titanium in complex solid solutions of the TiC-TiN system

The authors investigated the fine structure of absorption spectra of titanium in solid solutions of the TiC-TiN system. It is shown that the degree of filling of the 3d-band of the metal and the nature of its interaction with metalloid atoms remains practically unchanged.

Fine Structures of X-ray K Absorption Spectra of Nickel in Oxides of Nickel

The fine structures of X-ray K absorption spectra of nickel in metallic nickel, NiO, Ni 2 O 3 and NiO 2 ·nH 2 O were photographed by a bent crystal spectrograph. The fine structures of absorption spectra of metallic nickel and NiO agree well with those published by previous authors, but those of Ni 2 O 3 do not coincide with those reported by Hayasi and Cauchois. Also Cauchois' data of Ni 2 O 3 do not coincide with Hayasi's data. This seems to be due to doubtful chemical structures of Ni 2 O 3 and it is supposed that the three specimens used by the three authors might have different chemical structures. The first absorption maxima A are much more pronounced with increasing oxygen proportion and the general features of α, β, C and γ of the absorption spectra of oxides are similar respectively. However, the second small absorption maxima B are less pronounced with increasing oxygen proportion. These facts are expected from Coster and Kiestra's and Cauchois' considerations. It may be considered from the comp...

The Free-Electron Model, "Overtone" Bands, and Vibrational Structure in Absorption Spectra of Polyenes and Polyenynes.

The Free-Electron Model, "Overtone" Bands, and Vibrational Structure in Absorption Spectra of Polyenes and Polyenynes.

A method of absorption spectrography for the detection of the detailed structure of absorption spectra

A photographic plate is moved by means of a cam past the spectral image of the slit of a spectrograph at a logarithmically increasing rate. The plate obtained is suited to the detection of detailed structure of absorption spectra and, by use of a reference spectrum, to the quantitative estimation of absorption.