Vibrational properties of crystals with TlSe type structure

The lattice vibration spectra of TlS and TllnSe₂ crystals were investigated by infrared reflectivity in the wavenumber range from 20 to 5000 cm^?1. The frequencies of K = 0 phonons were determined by Kramers-Kronig analysis of the spectra. All five infrared active lattice vibrations predicted by the group theoretical analysis were identified. The normal coordinates of vibrations for five infrared active phonons were determined. In the approximation which does not take into consideration long range Coulomb interaction values of the force constant and effective changes are obtained for TlSe, TlS and TllnSe₂ crystals.     

The influence of hydrostatic pressure on Raman spectra of TIS and TlInSe2

First order Raman spectra of TIS and TlInSe₂ single crystals excited with 1.064μm line of the continuously operated YAG: Nd³⁺ laser have been investigated in equilibrium conditions under various hydrostatic pressures up to 1.08 × 10⁹ and 7.06 × 10⁸ Pa, respectively. Mode parameters γ_j = (1/ν_j)(dν_j/dP) were determined for all the Raman bands observed. Comparison of a set of these parameters in both crystals showed that the character of binding interatomic forces in these crystals appeared to be similar. For both crystals the intensity of Raman bands decreased with increasing the pressure.     

Ab initio calculation of vibrational spectra of orthorhombic IV–VI layered crystals

Phonon modes of IV–VI semiconductor crystals with the orthorhombic structure of the crystal lattice have been calculated from first principles using the linear response method. The calculations are compared with the results of theoretical calculations available in the literature for some of the crystals and with the experimental data obtained by IR and Raman spectroscopies. Equilibrium lattice parameters and phonon spectra are calculated for all the crystals.     

Analysis of the Products from the Reaction of L-Cysteine with Fe(III) Compounds in Acidic Medium

Journal of Applied Spectroscopy - The reaction of L-cysteine solution with the iron(III) compounds FeCl3, Fe2(SO4)3, and Fe(NO3)3 in an acidic medium (pH 2) was studied. The reaction was complete...