The influence of fast neutron irradiation on the IR optical properties of NTD-Silicon

Optical IR measurements of NTD-Si are presented for different fast neutron doses. The exponential dependence of the divacancy concentration and the near-edge absorption as a function of fast neutron flux is reported. Silicon one-phonon absorption, caused by the irradiation, is also increasing with the rising percentage of fast neutrons in the flux     

Total electron yield XANES of zinc-blende MnTe

The electronic structure and chemical bond of zinc-blende (zb) MnTe have been studied by using total-electron-yield (TEY) X-ray absorption near-edge structure (XANES) spectroscopy. Close resemblances of the shape of Mn K-edge XANES in zb-MnTe and in Zn_1−xMn_xTe [A. Titov, X. Biquard, D. Halley, S. Kuroda, E. Bellet-Amalric, H. Mariette, J. Cibert, A.E. Merad, G. Merad, M.B. Kanoun, E. Kulatov, Yu.A. Uspenskii, Phys. Rev. B 72 (2005) 115209] indicated predominant influence of the 1st coordination shell. In particular, identical single-peak pre-edge structure for both cases was mainly ascribed to the Mn 1s-3d/4p weakly allowed dipole transitions. The quantitative analysis of XANES in zb-MnTe concerned the observed chemical shift of Mn K-edge threshold energy and a magnitude of the relevant cation-anion charge transfer (or effective cation charge), q(Mn-Te) [calculated after M. Kitamura, H. Chen, J. Phys. Chem. Solids 52 (1991) 731]. It also provided a comparison with our earlier X-ray absorption studies of Zn_1−xMn_xB alloys (B = S, Se). The estimated charge transfer within the chemical bond of zb-MnTe enabled us to complete the q(Mn-B) versus chalcogen ligand (B = S, Se, Te) dependence and to interpret it in terms of p-d hybridization and a contribution of Mn 3d electrons to the overall charge transfer.     

Dynamic scaling and slowing down in chemical reactions of the critical triethylamine-water system

Between 100 kHz and 1 MHz, special ultrasonic attenuation measurements of the triethylamine-water mixture of critical composition have been performed for the determination of the Bhattacharjee-Ferrell scaling function. The experimental data are evaluated considering two noncritical Debye-type relaxation terms as revealed by broadband ultrasonic spectra. Shear viscosity and dynamic light scattering data from the literature are re-evaluated to yield the relaxation rate of order parameter fluctuations of the critical system as a function of temperature. The power law behavior found for the relaxtion rate fits to the scaling function in the ultrasonic spectra. The relaxation times of the noncritical Debye terms display a non-Arrhenius temperature dependence, pointing at effects of slowing in the chemical reactions associated with the relaxations.