Journal ArticleDOI
The investigation of atomic motions in crystalline, amorphous and liquid selenium, and in crystalline and liquid tellurium by neutron spectroscopy
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In this article, the energy spectra of monochromatic neutrons scattered on selenium and telllurium have been investigated by means of a rotating crystal spectrometer.Abstract:
The energy spectra of monochromatic neutrons scattered on selenium and telllurium have been investigated by means of a rotating crystal spectrometer. In polycrystalline selenium the highest spectral line can be identified as an intrachain bond stretching mode. Transforming selenium from its crystalline to its amorphous and liquid state, the shift of the line energy is only a few percent. The other lines in the spectra (from bond shearing and torsional modes of the chains) are influenced more strongly. For tellurium, on the other hand, the spectral lines of the solid disappear completely in the liquid phase. The experimental results are compared with the results of optical spectroscopy. Furthermore, the diffusive motion of the atoms has been studied by quasi-elastic neutron scattering for liquid selenium containing various admixtures of iodine (0–6 %), which change the average chain length of the polymeric melt, and for liquid tellurium. For Se, one obtains an effective diffusion constant D which describes the motion of small chain segments over atomistic distances. D is of the order of 10–5 cm2/s. Its activation energy was about 5 Kcal/mol.read more
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Journal ArticleDOI
A Relation Between Fast and Slow Motions in Glassy and Liquid Selenium
U. Buchenau,R. Zorn +1 more
TL;DR: In this paper, atomic mean square displacements for frequencies above 1011 Hz have been determined from neutron time-of-flight data in the glassy, liquid and crystalline phase of selenium.
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Quasielastic Neutron Scattering for the Investigation of Diffusive Motions in Solids and Liquids
TL;DR: Quasielastic neutron scattering for the investigation of diffusive motions in solids and liquids was proposed in this paper, where the authors proposed a method for diffusive motion in liquids and solids.
Journal ArticleDOI
Change of bonding system in liquid SexTe1−1 alloys as shown by density measurements
TL;DR: In this paper, an anomalous behaviour of the density was observed on melts in the binary chalcogenide system SexTe1−x up to a temperature of 950°C.
Journal ArticleDOI
First-principles molecular-dynamics simulation of liquid and amorphous selenium.
D. Hohl,Robert O. Jones +1 more
TL;DR: A molecular-dynamics simulation has been carried out for liquid and amorphous selenium in the temperature range 350\char21{}720 K, and special emphasis is given to the concentration, structure, and stability of the dominant defects.
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First-principles molecular-dynamics simulation of liquid and amorphous selenium.
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