Propagation of heat in anthracene crystals at helium temperatures

Measurement of temperature pulses with time resolution less than 5 nsec based, on the high-speed registration of the Debye-Waller factor in the fluourescence spectrum of an impurity layer deposited on a sample, has been achieved. In anthracene single crystals, the velocity of heat propagation was found to be equal to 0.7?1.0.10⁵ cm/sec, approaching that sound; the mean free path of phonons was found to exceed 30 μm.     

Kinetic analysis of photoelectrochemical hydrogen evolution over p-type silicon in acidic aqueous solutions of electrolytes

The kinetics of photoelectrochemical hydrogen evolution at p-Si single crystals in acidic aqueous solutions of electrolytes under pulse photoexcitation was studied. Despite a low stability of the silicon surface under the experimental conditions, a distinct interrelation between the characteristic time of interfacial charge transfer and stationary current was found. The determination of the characteristic transfer time does not need the detailed elaboration of generation-recombination processes in the semiconductor. The steady-state current density was shown to be determined both for the dark current and photocurrent by the surface charge density. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1724–1728, October, 2000.     

Hydrogen Evolution Efficiency at Illuminated Silicon

The change of kinetic characteristics of photoelectrochemical hydrogen evolution at p-type silicon in acid aqueous electrolyte solutions under prolonged continuous illumination is studied. It is shown that, during the transfer of full charge Q _t < 150 C/cm² through the silicon/electrolyte interface, the interrelation between the reciprocal time of the charge transfer into electrolyte and the steady-state current remains linear. In this case, a Tafel-like relation links the interfacial charge to the steady-state electrode current. Passing current through the electrode even further results, at Q _t > 350 C/cm², in breaking-down the direct relation between the current and the charge transfer time, despite the electrode's retaining high photosensitivity. The effect is probably caused by significant energy and structure distortions in the surface layer of silicon.     

Formation of methyl platinum complex in the reaction of methane with chloroplatinic acid

The¹HNMR method and chemical analysis indicate that a complex of Pt(IV) containing a CH₃–Pt fragment is formed in the reaction of H₂PtCl₆+H₂PtCl₄ with methane at 120 °C in aqueous CF₃CO₂H. The complex was isolated from the solution as an adduct of Ph₃P.

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, H₂PtCl₆ H₂PtCl₄ CF₃COOH 120°C (IV), Pt–CH₃. Ph₃P , .