Experimental studies of both reflection and wavelength derivation reflection spectra from freshly cleaved SrO and BaO crystals at 55 K are presented. The data are interpreted in a manner consistent with optical data on MgO and CaO crystal surfaces, in terms of I?-, X-, and L-excitons.Es werden experimentelle Untersuchungen der R*eflexionsspektren und der nach der Wellenlange abgeleiteten Reflexionsspektren an frisch gespaltenen SrO-und BaO-Kristallen bei 55 K durchgefiihrt. Die Werte werden mittels I'-, X-und L-Exzitonen in einer Weise interpretiert, die mit optischen Daten an MgO-und CaO-Kristalloberflllchen konsistent ist.

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The feasibility of producing titanium metal from titanium tetrachloride in a thermal plasma under equilibrium and adiabatic expansion conditions has been theoretically investigated. Free energy minimization and adiabatic expansion calculations to simulate a nozzle expansion were used to stud), the practicality of production. The crucial requirements for tbe production of titanium powder from TiCI4 and 1"12 appear to be rapid quenching of the plasma gas at high temperature (e.g., 3700 K) and appropriate reactant concentrations. Quenching of the plasma gas and production of titanium powder can be achieved by adiabatic expansion througb a nozzle. Preliminary experimental data indicate that titanium powder of approximately 5 nm in size can be produced in an argon plasma using a nozzle expansion approach.

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