What Oxidation State of Iron Determines the Amethyst Colour?

A colourless quartz crystal doped with ⁵⁷Fe³⁺ was obtained by hydrothermal synthesis in an NH₄F solution. The crystal was transformed into violet amethyst by gamma-irradiation. The change in colour was accompanied by changes in the Mössbauer spectrum that can be interpreted as the conversion of trivalent iron into the tetravalent state: Fe³⁺→Fe⁴⁺.

     

Generation of high-energy negative hydrogen ions upon the interaction of superintense femtosecond laser radiation with a solid target

The formation of a high-energy (～35 keV) beam of negative hydrogen ions was observed in the expanding femtosecond laser plasma produced at the surface of a solid target by radiation with an intensity of up to 2× 10¹⁶ W/cm². The energy spectra of the H⁺ and H^?-ions show a high degree of correlation.     

Dislocation theory of the energy loss during remagnetization of a ferromagnet. II

The effect of a dislocation on the motion of domain walls of various types, which may bend during displacement, is analyzed. The energy loss is calculated for the case in which a ferromagnet is remagnetized through displacement of domain walls interacting with dislocations. The internal friction, due to the interaction of domain walls with dislocations at a varying mechanical stress, is also calculated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 67–74, July, 1972.     

Synthesis and some properties of vanadocene isocyanate and isothiocyanate d1-complexes

Conclusions Vanadocene monochloride and vanadocene dichloride react with organotin and organosilicon pseudohalides, R₃MNCX (R₃M=Bu₃Sn, Me₃Si and X=O, S), to give the corresponding vanadium (IV) d¹-complexes, Cp₂V(NCX)₂ or Cp₂VCl(NCX).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 678–681, March, 1988.     

Solubility of additives in polyethylene and aliphatic polyamides. The effect of oxidation

The solubility of diphenylamine, phenyl benzoate and diphenyl methane in high-density polyethylene and various polyamides has been studied as a function of oxidation and of sample annealing.

Oxidative destruction of topological structures forming the non-polar sorption centers and accumulation of new-formed polar groups, participating in sorption of polar compounds, result in complicated dependencies of solubility upon oxidation, in some cases showing minima.     

Unstable complexes of sandwich compounds and small molecules. 5. Complex formation of carbon dioxide molecules with organometallic compounds of transition elements at low temperatures

Conclusions CO complexes with the cyclopentadienyl and arene complexes of transition metals are formed at 80–90 and 14–16 K on a cold substrate by direct synthesis. The structures of the complexes depend on experimental conditions.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2298–2301, October, 1988.