Radiative transitions involving the (2p2)(3 Pe) metastable autodetaching of H(-)

The absorption coefficient for the free-bound transition H (ls) + e(-)+ h omega yields H(-)(2 sq p,(3)P(e)) is calculated (together with the differential emission rate for the inverse process) using ls - 2s - 2p close coupling continuum wave functions and a Hylleraas bound state wave function. A maximum in the absorption and emission spectra is found to occur at a photon wavelength of 1219.5 A, which is 2 A closer to the Lyman alpha line than predicted by the calculations of Drake, and is in closer agreement with the stellar absorption feature identified by Heap and Stecher. The free-bound absorption process appears to be a significant source of continuous ultraviolet opacity

Relative Riemann-Zariski spaces

In this paper we study relative Riemann-Zariski spaces attached to a morphism of schemes and generalizing the classical Riemann-Zariski space of a field. We prove that similarly to the classical RZ spaces, the relative ones can be described either as projective limits of schemes in the category of locally ringed spaces or as certain spaces of valuations. We apply these spaces to prove the following two new results: a strong version of stable modification theorem for relative curves; a decomposition theorem which asserts that any separated morphism between quasi-compact and quasi-separated schemes factors as a composition of an affine morphism and a proper morphism. (In particular, we obtain a new proof of Nagata's compactification theorem.)Comment: 30 pages, the final version, to appear in Israel J. of Mat

Operation of a step tunable megawatt gyrotron

An electron cyclotron resonance maser; gyrotron fundamental oscillator; advantages of gyrotrons; a schematic of the experiment; gyrotron design theory; 1 MW design parameters; compact ignition tokamak; and a gyrotron with quasi-optical output coupler are briefly presented. This presentation is represented by viewgraphs only

Initial growth of interfacial oxide during deposition of HfO2 on silicon

doi:10.1063/1.1771457Interfacial chemistry of Hf∕Si, HfO2∕SiO2∕Si, and HfO2∕Si is investigated by x-ray photoelectron spectroscopy in order to understand the interfacial layer formation mechanism. Deposition of Hf and HfO2 films was carried out on Si wafers by electron-beam evaporation with oxygen backfill. We show that the interfacial layer formation takes place predominantly at the initial stage of the HfO2 film deposition. Temporary direct bonding between Hf metal and Si is proposed to be the source of the catalytic reaction resulting in formation of interfacial layer. Formation of interfacial layer was suppressed by chemically grown thin oxide blocking the direct Si-Hf bonding. We also demonstrate reduced interfacial layer after modified Shiraki surface etch, compared to the Radio Corporation of America clean. This indicates that a more complete hydrogen termination and atomically smoother surface can delay the onset of interfacial layer formation