Reflectivity measurements on hot reactive liquids using an FIR laser

The experimental procedures and precautions required to measure liquid-alloy reflectivities with a cw far infrared (FIR) laser are described. The output of a carefully stabilized optically pumped FIR laser was channeled to a melted sample contained in a silica holder under a He atmosphere. By maintaining specular reflection and alloy homogeneity, reflectivities reproducible to ± 7% were routinely obtained

Research Funding by City: An Indicator of Regional Technological Competitiveness

Research and development (R&D) expenditures are an important input to the development of intellectual property and human capital in an economy. This paper explores the way peer-reviewed funds are distributed in a nation whose economy is based on a number of different regional economies

Far-Infrared Properties of Lattice Resonant Modes. V. Second-Order Stark Effect

Small electric-field-induced frequency shifts have been observed for resonant modes associated with three defect systems. For NaI: Clˉ, the shifts have been used to measure the quartic anharmonic terms of the interionic potential of the impurity ion. For KBr: Li+, the quartic anharmonic terms are found to be very small, and an harmonic potential which includes a central barrier with the barrier height less than the zero-point energy of the oscillator is required to explain the experimental results. For NaCl: Cu+, only an on-center resonant-mode configuration is consistent with the experimental results

Far infrared reflectivity of liquid Ga-Te alloys

he far infrared (FIR) reflectivities of liquid Ga–Te alloys as a function of composition, temperature, and frequency have been measured using both a far infrared laser and Fourier-transform spectroscopy. The reflectivity R is anomalously enhanced between the compositions GaTe and Ga2Te3, suggesting molecular clustering in this alloy range. The temperature dependence of R appears to correspond to an activated conductivity, and is strongest near Ga2Te3. The variation of R with frequency for the stoichiometric alloys is Drude-like at higher frequencies, but is nearly constant below 175 cm−1 for GaTe. The FIR conductivities extrapolated to zero frequency are significantly larger than the direct current (dc) values. The data are similar to liquid Mg–Bi measurements and to the spectra of several amorphous glasses. The composition dependence of R is consistent with a superposed band model for ionic constituents with some covalent bonding. Agreement of the frequency dependence of R with experimental values requires a small constant density of states at the Fermi energy