Core-exciton induced resonant photoemission in the covalent semiconductor black phosphorus

Valence band photoemission spectra of black phosphorus have shown anomalous behavior at the excitation of 2p core-excitons. The intensity of the 2.7 ev peak shows a clear Fano type interference due to a direct recombination of core-excitons leaving one hole in valence bands. Besides, strong enhancement of the 10.8 eV peak is interpreted as due to a core-exciton induced resonance with two-hole final states. The role of core-excitons as intermediate states for photoemission processes is newly revealed in the experiments.     

Monooxygen transfer potential of the transannular ozonide of 9-tert-butyl-10-methylanthracene

The efficiency of oxygen transfer from the transannular ozonide 1 to several organic substrates was investigated. The efficiency was estimated to be as high as 90% in the case of Ph₃P as the substrate.     

Microwave spectroscopy of the CCl radical

The CCl radical was generated by a dc glow discharge in CCl₄, and rotational transitions of C³⁵Cl in both ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ were observed in the mm-wave region by using a source modulation microwave spectrometer. From an analysis of the observed spectra the magnetic and electric quadrupole hyperfine coupling constants of the ³⁵Cl nucleus were determined precisely. The Λ-doubling constant p₀ was determined to be positive, indicating that unknown ²Σ^? excited electronic states are making dominant contributions to the Λ doubling in the ground state. The previous diode-laser result [J. Mol. Spectrosc.85, 416–426 (1981)] was reanalyzed by using improved wavelength standards and by fixing the ground-state parameters to the present microwave values including the B₀ rotational constant 20 797.1725(38) MHz. The vibration-rotation constant α^B and the equilibrium bond length r_e were thus determined to be 0.006 768 2(48) cm^?1 and 1.645 218(16) Å, respectively, with 2.5 times standard deviations in parentheses. The spin density on the chlorine atom was estimated to be about 0.20 from the observed hyperfine coupling constants.     

Coherent Raman beats associated with superhyperfine structure in ruby

Coherent Raman beats associated with superhyperfine structure (shfs) due to Cr-Al interaction were observed in ruby. The rf modulated Stark field was used to create coherences between shfs sublevels under the irradiation with a cw ruby laser. From the beat frequencies high resolution spectra of shfs with width (HWHM) of about 10 kHz were obtained in the frequency range from about 4.5 to 6.5 MHz. The utility of phase sensitive detection technique combined with rf Stark modulation was demonstrated. The observed spectra were compared with the theoretical ones.     

Elasto-plastic bending of an annular plate at large deflection

Summary The elasto-plastic bending of a simply supported annular plate with a free inner edge upon which an uniformly distributed lateral load acts is theoretically investigated, taking into account the influence of the membrane forces. A homogeneous and isotropic elasto-perfectly-plastic material satisfying the Mises' yield condition and the Hencky's stess-strain relation is assumed. The theoretical results are discussed and compared with experimental results obtained with a plate of mild steel; the relation between the real behavior of the actual material and the usual assumptions used in the analysis is emphazised. The theoretical result is also compared with the result of an analysis in which the membrane forces were neglected; in this manner the influence of these forces is shown.

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Übersicht Das elastisch-plastische Biegen einer einfach gelagerten Ringplatte wird theoretisch untersucht, wobei der Einfluß der Membrankräfte berücksichtigt wird. Der innere Rand der Platte ist frei gelagert und trägt eine stetig verteilte Querlast. Es wird ein homogenes, isotropes und ideal elastisch-plastisches Material vorausgesetzt, das der v. Misesschen Fließbedingung und dem Henkyschen Spannungs-Dehnungs-Gesetz genügt. Die Rechenergebnisse werden diskutiert und mit entsprechenden Versuchsergebnissen verglichen, wobei besonderen Wert auf die Beziehung zwischen dem wirklichen Materialverhalten und den üblicherweise in der Theorie verwendeten Annahmen gelegt wird. Die Ergebnisse werden außerdem mit entsprechenden Berechnungsergebnissen verglichen, bei denen die Membrankräfte vernachlässigt wurden, so daß der Einfluß dieser Kräfte deutlich wird.

     

Fluorination of double-walled carbon nanotubes

Fluorine atoms are selectively attached to the sidewall of the outer shell of DWNTs without disrupting the double-layered morphology; the stoichiometry of the fluorinated DWNTs is CF(0.30).