Optical and electronic properties of siloxane-bridged cyclic dimers with naphthylene or pyrenylene moieties

The optical and electronic properties of novel siloxane-bridged cyclic dimers with naphthylene (CD1) or pyrenylene (CD2) moieties are described. CD1 and CD2 were obtained by the cyclic dimerization of 1,4-bis(dimethylhydroxysilyl)naphthalene (M1) and 1,6-bis(dimethylhydroxysilyl)pyrene (M2), respectively. CD1 and CD2 mainly exhibited the emission from their excimers owing to their short distances between aryl moieties in CD1 and CD2, which were determined to be 3.44 Å and 3.41 Å by the X-ray crystallographic analysis, respectively. The absorption spectra of CD2 in the presence of 7,7,8,8-tetracyanoquinodimethane (TCNQ) revealed that CD2 has the ability to form 1:1 charge-transfer complex with TCNQ, indicating the existence of the transannular π-π interaction between closely located pyrene components in CD2.     

Comparative extreme ultraviolet emission measurements for lithium and tin laser plasmas

Detailed spectroscopic studies on extreme UV emission from laser plasmas using tin and lithium planar solid targets were completed. At 13.5 nm, the best conversion efficiency (CE) for lithium was found to be 2.2% at intensities near 7 x 10(10) W/cm(2). The highest CE measured for tin was near 5.0% at an intensity close to 1 x 10(11) W/cm(2).     

Electron excitation of the Schumann-Runge continuum, longest band, and second band electronic states in O2

We report measurements of differential and integral cross sections for electron excitation of the Schumann-Runge continuum, longest band, and second band electronic states in molecular oxygen. The energy range of the present study is 15-200 eV, with the angular range of the differential cross section (DCS) measurements from 2 to 130°. A generalized oscillator strength analysis is then employed in order to derive integral cross sections (ICSs) from the corresponding DCSs, and these ICSs are compared with relevant energy and oscillator strength scaled Born cross section (BEf-scaling [Y.-K. Kim, J. Chem. Phys. 126, 064305 (2007)]) results determined as a part of this investigation. Interestingly, while the present Schumann-Runge continuum and second band ICSs were in reasonable agreement with the respective BEf-scaling results, agreement for the longest band was poor below 100 eV with a possible reason for this apparently anomalous behavior being canvassed here. Finally, where possible all present data are compared with the results from earlier measurements and calculations with the level of agreement found being very good in some cases and marginal in others.     

Photoemission study on the valence band of a β-FeSi2 thin film using synchrotron radiation

Resonant and constant-initial state photoemission spectroscopies using synchrotron radiation were applied to investigate the valence-band electronic structure of a semi-conducting β-type iron-disilicide (β-FeSi(2)) thin film. The results clearly indicated that the component elements, iron (Fe) and silicon (Si), contribute differently to the valence band features; the Fe 3d orbitals mainly concentrate in the top region of the valence band while the Si 3s and 3p orbitals spread over the wide region of the valence band. The β-FeSi(2) thin film showed a typical p-type semi-conducting nature with a work function of 4.78 eV. The β-FeSi(2) film showed the Fe M(1)VV Auger lines around the kinetic energy of 88 eV. It would be expected from these observations that there exist strong interactions between iron and silicon atoms in the β-FeSi(2) film resulting in orbital mixing and band formation.     

Identification of gas emanated from human skin: methane, ethylene, and ethane.

We investigated whether methane, ethylene and ethane gas can be detected in gas emanating from human skin, which is called skin gas. Skin gas was collected with a homemade stainless-steel trap system, which was cooled with liquid nitrogen, and analyzed with a gas chromatograph fitted with a flame ionization detector (FID). Skin-gas samples were obtained by covering a hand for 30 min with a polyfluorovinyl bag in which pure helium gas was introduced. The bag, the trap system and GC were set up online to avoid any contamination by air. Methane, ethylene and ethane in skin gas were successfully collected at an average amount emanated for 30 min (from ten subjects) of 150 +/- 63, 20 +/- 11 and 17 +/- 8 [mean +/- SD] pg/cm2, respectively.     

Synthese und Polymerisation von 10-[Bis(benzyloxy)phosphoryloxyldecylmethacrylat

Ohne Zusammenfassung     

Raman linewidth study of hydration structure of p-dioxane in aqueous solution

The isotropic linewidth of the CO stretching Raman line of p-dioxane at 835 cm^?1 has been measured at a variety of concentration in aqueous solution and in nonpolar tetrachloroethylene solution. The hydration structure of p-dioxane in aqueous solution has been investigated by a comparison of the experimental results obtained here with those for t-butyl alcohol in the preceding study. As a result, the present data prefer to the hydrogen-bond model rather than the clathrate model, proposed for the p-dioxane-water system.