scholarly journals IR-Spektren kristalliner, wasserfreier Permanganate, Pertechnetate und Perrhenate

1966 ◽  
Vol 21 (1) ◽  
pp. 3-7 ◽  
Author(s):  
Achim Müller ◽  
Bernt Krebs
Keyword(s):  
Ir Spectra ◽  
Crystal Field ◽  
Infrared Absorption ◽  
Group Analysis ◽  
Factor Group ◽  
Site Group ◽  
Absorption Frequencies

The infrared absorption frequencies in the region of the MeO4⊖ fundamental vibrations are reported for several crystalline permanganates, pertechnetates, and perrhenates. On the basis of the IR spectra of the crystals and of additional considerations correct frequencies are assigned to the ν2(E) vibrations of the MeO4⊖ tetrahedra. The influence of the crystal field on the fundamental vibrations of the MnO4⊖, TcO4⊖, and ReO4⊖ ions is discussed, using site group analysis and factor group considerations.

Infrared absorption spectra of Ag3[PO4, VO4] mixed crystals

1979 ◽  
Vol 44 (3) ◽  
pp. 823-828 ◽  
Author(s):  
Bohumil Hájek ◽  
Alexander Muck ◽  
Olga Smrčková
Keyword(s):  
Mixed Crystal ◽  
Group Analysis ◽  
Factor Group ◽  
Mixed Crystals ◽  
Site Symmetry ◽  
Lattice Vibrations ◽  
Concentration Region ◽  
Site Group ◽  
Infrared Absorption Spectra ◽  
Effective Site

Ag3[PO4, VO4] mixed crystals were prepared in the whole concentration region. For 0-40 mol % vanadate, the mixed crystals are isostructural with the low-temperature modification of Ag3PO4 (Td4, Z = 2); the site group and factor group analysis was performed for this space group. Mixed crystals containing 60% vanadate and more are tetragonal with the structure of Ag3VO4. From the analysis of the infrared spectra it follows that in the cubic mixed crystal with 40 mol % Ag3VO4, the site symmetry T is additionally lowered to the effective site symmetry C3 due to the effect of the lattice vibrations of the types T(F) and R(F).

Raman study of the structural properties of KNO3(II)

1977 ◽  
Vol 55 (7) ◽  
pp. 1242-1250 ◽  
Author(s):  
M. H. Brooker
Keyword(s):  
Single Crystals ◽  
Structural Properties ◽  
Raman Spectra ◽  
Excellent Agreement ◽  
Room Temperature ◽  
Group Analysis ◽  
Factor Group ◽  
Spectral Features ◽  
Space Group ◽  
Raman Study

Raman spectra of oriented single crystals of KNO3(II) have been recorded at 298 and 77 K. At both temperatures the data are in excellent agreement with the factor group analysis based on the generally accepted Pmcn space group. Additional spectral features observed near room temperature suggest the presence of a significant number of disordered nitrate groups on alternate lattice sites, although the majority of nitrate groups occupy the ordered sites. As the temperature is lowered, the disordered groups freeze out until near the temperature of reported electrical anomalies (213 K) only the ordered sites are occupied. Improved resolution has resulted in detection of a number of new spectral features while improved depolarization data have resulted in reassignment of several peaks.

Raman Scattering Studies on Superconducting YBa2Cu3O7−x, Semiconducting YBa2Cu3O6+x, and Possible Impurity Phases

1987 ◽  
Vol 99 ◽  
Author(s):  
A. Mascarenhas ◽  
H. Katayama-Yoshlda ◽  
S. Geller ◽  
J. I. Pánkové ◽  
S. K. Debt
Keyword(s):  
Critical Temperature ◽  
Raman Scattering ◽  
Temperature Dependence ◽  
Phonon Mode ◽  
Group Analysis ◽  
Factor Group ◽  
Anomalous Temperature Dependence ◽  
Anomalous Temperature ◽  
Mode Softening ◽  
Characteristic Lines

ABSTRACTA Raman spectroscopie investigation of specimens of superconducting YBa2Cu3O7−x and semiconducting YBa2Cu3O6+x indicates that in the range 100 to 700 cm-1, the characteristic lines of the superconductor at 13 K, are at 150, 338, 441, 507, 590, and 644 cm-1. Comparison of the Ranan spectra of the superconductor and the semiconductor indicates a mode stiffening of the pair at 338 and 441 cm-1, hut a mode softening of the pair at 507 and 590 cm-1. A factor group analysis leads to a tentative assignment of the Raman and infrared allowed modes. At temperatures 12K < T < 180K the Raman spectra of the superconductor indicate that the phonon mode at 338 cm-1 has an anomalous temperature dependence below the superconducting critical temperature (Tc).

Vibrational spectra and factor-group analysis of double arsenates of zirconium and alkali metal MZr2(AsO4)3 (M=Li–Cs)

2014 ◽  
Vol 73 ◽  
pp. 158-163 ◽  
Author(s):  
E.Yu. Borovikova ◽  
V.S. Kurazhkovskaya ◽  
K.N. Boldyrev ◽  
M.V. Sukhanov ◽  
V.I. Pet’kov ◽  
...  
Keyword(s):  
Alkali Metal ◽  
Vibrational Spectra ◽  
Group Analysis ◽  
Factor Group ◽  
Factor Group Analysis
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