The spectra of stimulated emission, observed in the process of the H(2) + F(2) ? HF and D(2) + F(2) F(2)? DF reactions, were investigated and compared. The stimulated emission in the vibrational transitions up to 6-5 for the HF molecule and up to 9-8 for the DF molecule was discovered. It was found that the emission energy in the transitions of 2-1 and 5-4 bands in the H(2) + F(2) mixture was the highest possible. In the D(2) + F(2) mixture the emission energy maxima correspond to the 3-2 and 8-7 bands. The presence of the two maxima reflects the fact that the two types of chemical reactions contribute to the population inversion creation. One is a F + H(2)(D(2)) reaction, the other is a H(D) + F(2) reaction. By analyzing the characteristics of the chemical laser in which the energy exchange between the DF and CO(2) molecules takes place, the energy-transfer rate constant was estimated with the value being equal to (1.5 +/- 0.5) x 10(-12) cm(3) sec(-1).
Amorphous gallium films (thickness -9 nm) have been prepared by evaporation onto alow-temperaturesubstrate invacuum. Znsituopticalmeasurementsfrom0.5 to4.5 eV are analysed using Drude theory and produce a figure of 0.9 nm for the electron mean free path.Electrical measurements confirm the presence of the amorphous phase, and the results are consistent with earlier measurements on thick gallium films.
Thermoreflectance spectra of Pb,_,Ge,Te ( x = 0,0.02,0.03,0.07 and 0.1) have been investigated in the energy range 1.2 to 4.4 eV at temperatures above and below the phase transition temperature. The change of the interband transitions on the G e content x in the cubic phase (300 K) have been obtained. Thermoreflectance spectra in the range of the transition temperature are broad, the structures are not clearly pronounced, which does not give the possibility of following the changes of the band structure in the range of the phase transition. The thermoreflectance spectrum of the rhombohedral Pb, sGeo ,Teat 40 K, well below the transition temperature of the compound, indicates the appearance of three additional structures of M O type. These structures have been attributed to transitions at the critical points along the TW direction of the Brillouin zone.
Using three-dimensional magnetohydrodynamics simulations, we show that the efficiency of cosmic-ray (CR) production in supernova remnants is over-predicted if it could be estimated based on proper motion measurements of Hα filaments in combination with shock-jump conditions. Density fluctuations of the upstream medium cause shock waves to be rippled and oblique almost everywhere. The kinetic energy of the shock wave is transferred into downstream turbulence as well as thermal energy related to the shock velocity component normal to the shock surface. Our synthetic observation shows that the CR acceleration efficiency, as estimated from a lower downstream plasma temperature, is overestimated by 10%-40% because a rippled shock does not immediately dissipate all of the upstream kinetic energy.
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