Vibrational anharmonicity and vibrational Stark effect of sulfate ions trapped in potassium, rubidium and cesium chromate

Room and low temperature (approximately 100 K) FT-IR and Raman spectra of the sulfate doped K2CrO4, Rb2CrO4 and Cs2CrO4 were recorded. The positions of the nu1, nu3, and nu4 fundamental mode components of the dopant anions were measured. Nine (out of possible ten) second-order stretch-stretch vibrational transitions of the dopant anions were detected. On the basis of these data, the anharmonicity constants and the corresponding harmonic eigenvalues were calculated for several vibrational transitions using second-order perturbation theory expressions. The anharmonicity of the studied second-order transitions of the type nu1 + nu3i increases in the order (SO4/K2CrO4) < (SO4/Rb2CrO4) < (SO4/Cs2CrO4), while for those of the type nu3j + nu3i it basically follows the trend: (SO4/K2CrO4) > (SO4/Rb2CrO4) < (SO4/Cs2CrO4). The measured relative Stark splittings of the nu3 and nu4 mode components of the dopant SO4(2-) anions, as well as the average X13i/3i3j values decrease in the order (SO4/K2CrO4) > (SO4/Rb2CrO4) > (SO4/Cs2CrO4). In all cases, the splitting is larger for nu3 than for nu4 modes, indicating a smaller angular than the bond length distortion. The theory of vibrational Stark effect suggests that the observed frequency shifts of the nu1, nu3 and nu4 mode components may be attributed to the increase of the field strength at the doped anion site going from K2CrO4 to Cs2CrO4. The Stark splitting of these modes, on the other hand, implies that the internal crystalline field vector is almost parallel to the (hypothetical) C2 axis of the slightly distorted dopant tetrahedral anions.     

Chemistry and sequence of conversions during reaction of potassium,rubidium, and cesium molybdates with aluminum,gallium, and indium sulfates

Conclusions In the systems alkali-metal molybdater-ammonium, gallium, or indium sulfate, at a 11 ratio of the components we observe only addition reactions with formation of double molybdate sulfates MR[(MoO₄)_0.5·(SO₄)_1.5]. Some of their physicochemical properties have been investigated.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 935–936, May, 1979.     

Cadmium vanadates of potassium,rubidium, and cesium

The solid-phase reactions between the components have been used to study the equilibrium phase composition of the systems M₂O(M₂CO₃)-CdO-V₂O₅ (M = K, Rb, or Cs) in the range of the subsolidus temperatures. New potassium cadmium vanadates KCd₃V₃O₁₁, K₂Cd₅(VO₄)₄, and K₂Cd₄V₄O₁₅ have been synthesized. A monoclinic solid solution has been identified on the basis of the KCd₄(VO₄)₃ structure. Double orthovanadate RbCdVO₄ has been prepared for the first time. Equilibrium phase diagrams have been constructed using both previously known compounds, and those synthesized by us. The effect of the size factor (the M⁺ ion radius) on the phase formation and phase equilibria in the systems in question has been traced.     

Stark broadening and shift of neutral iodine lines and regularities for analogous transitions of halogene atoms

We report results of an experimental study of the Stark broadening and shift of fourteen and eight neutral iodine lines, respectively, in a plasma wall stabilized arc. An electron density of about 2 × 10²² m^?3 was determined from the width of H_α line, while an electron temperature about 9300 K was derived from plasma composition data. The agreement within 40% of both experimental Stark widths and shifts with results of simple theoretical approach by Dimitrijevi? and Konjevi? is found. Results of the investigation of similarities of neutral iodine Stark widths are in agreement with the study of Wiese and Konjevi?. Comparison of experimental Stark shift shows similar types of regularities. Comparisons of Stark widths along analogous transitions of halogene atoms show an increase of widths from fluorine to iodine. It has been demonstrated also that Stark shifts for the same transitions show similar behaviour.     

Investigations on potassium and rubidium uranates

A systematic study of the KUO and RbUO systems is presented. In both systems four distinct uranates-VI with metal/uranium ratio's 2.0, 1.0, 0.5 and 0.286 exist. At low oxygen pressures only one uranate with formula MUO₃ is stable in both systems. X-ray powder data of all compounds are presented. Conflicting data in the literature are discussed.     

Thermal decomposition stages of potassium,rubidium and caesium permanganates

Thermal decomposition of KMnO₄, RbMnO₄ and CsMnO₄ have been investigated. Stage mechanisms of the thermal decomposition on the basis of the morphological classification have been proposed.

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Zusammenfassung Es wurde die thermische Zersetzung von KMnO₄, RbMnO₄ und CsMnO₄ untersucht. Auf der Basis der morphologischen Klassifizierung wurde ein Mechanismus für die thermische Zersetzungsreaktion vorgeschlagen.

     

Optical properties and paramagnetic susceptibility of europium gallium garnet

A single crystal of europium gallium garnet has been grown by the flux method and the experimental variation with temperature of its paramagnetic susceptibility has been studied up to 600 K. The crystal field parameters have been calculated for D₂ symmetry. From the derived wavefunctions, the magnetic susceptibility versus temperature was calculated. The experimental and simulated susceptibilities are in good agreement.     

Indirect complexometric titration of potassium,rubidium, cesium,thallium and ammonium

A titrimetric method using EDTA for the determination of potassium, rubidium, cesium, thallium and ammonium has been developed. These cations are precipitated as M₂Ag[Co(NO₂)₆] and the blue cobalt thiocyanate complex in acetone-water mixed system is titrated with EDTA. Milligram quantities have been determined in the present work     

Thermal decomposition of potassium,rubidium and caesium fluoroantimonates(III)

The thermal decomposition of crystalline complexes of the types M₂[SbF₅], M[SbF₄], M[Sb₂F₇] and M[Sb₄F₁₃] (where M = K, Rb, Cs) was studied. Crystals were prepared by slight modifications of the methods described in the literature. On the basis of the results of thermal analyses the mechanisms of thermal decomposition were proposed. From thermogravimetric curves kinetic parameters were calculated using the methods of Coats and Redfern and Zsako. A comparison was made of the thermal stabilities in the light of available structural data.     

Reaction of potassium,rubidium, and cesium molybdates with aluminum and indium sulfates

Conclusions On the basis of the DTA and RPA data it was established that incongruently melting compounds of composition MR[(SO₄)_1.5·(MoO₄)_0.5] are formed in the investigated systems. The purity of the obtained compounds was confirmed using the IR spectroscopy method. Some of the physicochemical properties of these compounds were studied, and the parameters of the subcells were determined.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1151–1154, May, 1976.     

Possibility of separating potassium and rubidium nitrates,and potassium and cesium nitrates,by zone melting in ammonium nitrate

Conclusions The mutual effect of KNO₃ and RbNO₃, and of KNO₃ and CsNO₃, during the directed crystallization of NH₄NO₃ is not manifested on the values of the equilibrium distribution coefficients. The salts pairs: KNO₃-RbNO₃ and KNO₃-CsNO₃ can be separated by zone melting in ammonium nitrate.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2808–2809, December, 1971.     

Stark widths and shifts of SnI,HgII, HgIII and PbII spectral lines

Stark widths and shifts of neutral and ionized heavy atom spectral lines have been measured and calculated. The Stark parameters of three SnI (284.0, 286.3 and 303.4 nm), five HgII (226.2, 398.4, 222.5, 615.0 and 326.4 nm), two PbII (220.4 and 438.6 nm) and one HgIII (235.4 nm) spectral lines were measured for the first time except the Stark widths of one HgII (398.4 nm) and one PbII (438.6 nm) line. Stark width values for a number of corresponding transitions were calculated on the bases of semiclassical and semiempirical formulae.     

Modified semiempirical Stark shifts of ArII lines

Stark shifts for 47 multiplets of ArII are calculated according to modified semiempirical approach [1], and compared with critically selected [2, 3] experimental data [4–11] as well as with semiclassical values of Jones et al. [12], when available. Mean experimental to theoretical (modified semiempirical) shift ratio 1.38±0.60 is obtained.     

Stark shift and broadening of FI and ClI lines

We report measured Stark shifts and widths of neutral flourine and chlorine lines. Wall stabilized arc is used as a plasma source. Electron densities 2–4×10²² m^?3 are determined from the width of theH _β line and electron temperatures 9500–10 000 K from plasma composition data. Experimental results for FI and ClI Stark widths and FI Stark shifts agree within 10% with semiclassical calculations. ClI Stark shifts are systematically smaller for about 20% than theoretical data with the only exception of the line from multiplet no. 15 where the discrepancy goes up to 49%. Results of investigation of similarities and regularities of Stark widths are in agreement with the study of Wiese and Konjevi?. Comparison of experimental Stark shifts shows certain types of regularities.