Projection of Si 1s photoexcited orbitals into resonant Auger electron spectra in KLL decays of Si(CH3)4 and SiF4

Spectator resonant KL(23)L(23) Auger electron spectra have been measured in the Si 1s photoexcitation region of Si(CH(3))(4) using monochromatized undulator radiation combined with a hemispherical electron spectrometer. The broad peak with high intensity in a total ion yield spectrum, coming mainly from excitation of a 1s electron into the 6t(2) vacant orbital, induces a spectator Auger decay in which the excited electron remains in its excited orbital. The component on the higher energy side of this peak through 1s excitation into a Rydberg orbital produces resonant Auger decays in which the excited Rydberg electron moves into a slightly higher Rydberg orbital, or is partly shaken up to a significantly higher Rydberg orbital. These findings of Si(CH(3))(4) indicate a clear contrast to those for SiF(4), in which the 1s excitation into a Rydberg orbital induces a shake-down phenomenon as well as a shake-up one. The results of these molecules exhibit a clear splitting effect among excited orbitals which are smeared out by overlapping due to lifetime widths and due to densely populated levels in the 1s electron excitation spectrum. This is consistent with the calculation on photoexcitation within the framework of density functional theory.     

Effect of A Magnetic Field on Photophysical Processes of Molecules

A main purpose of this paper is to present a density matrix treatment of the magnetic quenching of molecular luminescence. Unlike the previous theories, which only consider the magnetic effect on the nonradiative rate constant, the present theory describes the time-evolution of the system under the action of a magnetic field. Our theory can treat both the steady state and transient molecular luminescence affected by a magnetic field.     

Magneto-optical spectroscopy of carbon nanotubes

We review our recent optical experiments on single-walled carbon nanotubes in high magnetic fields. The data revealed magnetic-field-induced optical anisotropy as well as broadening, splittings, and shifts of interband absorption and photoluminescence peaks. Quantitative comparison with theoretical predictions based on the Aharonov–Bohm effect is presented.     

Photoelectric cross-sections for fixed-orientation atomic orbitals: Relationship to the plane-wave final state approximation and angle-resolved photoemission

Differential photoelectric cross sections for fixed-orientation p- and d-orbitals have been derived within the one-electron, central-potential model and the dipole approximation for a completely general experimental geometry. Also, for the special geometry of a polarized source with polarization parallel to the electron emission direction, it is shown that such cross sections are exactly proportional to the probability distribution of the initial orbital, a result equivalent to that derived by using a plane-wave final-state approximation. Detailed numerical calculations of cross sections for Cu3 and O2p orbitals in various geometries and at various energies exhibit significant differences in comparison to plane-wave cross sections. By contrast, certain prior angular-resolved X-ray photoemission studies of single-crystal valence bands are found to have been carried out in an experimental geometry that fortuitously yields cross-sections close to the plane-wave predictions.     

The kinetic theory of magnetic-field generation in a Langmuir plasma

We develop a two-timescale kinetic theory for the nonlinear generation process for a slow-timescale magnetic field in a hot collisionless Langmuir plasma. We show that the basic damping of this magnetic field is due to the collisionless skin effect.     

Effects of dynamical friction on the renormalization of propagator in turbulent plasmas

It is shown that there appear two stages in effects of fluctuations on particle trajectories in weakly turbulent plasmas. A new propagator including dynamical friction is obtained, which is different from the Dupree type one.     

The valence band structure of metal hexaborides: An ESCA study of CaB6, and YB6

Two typical hexaborides CaB₆ and YB₆ have been studied by X-ray photoelectron spectroscopy (XPS or ESCA). The ESCA spectra of these compounds in the energy band region can be explained successfully by the calculation of Longuet-Higgins and Roberts rather than those of other authors. This means that covalent bonding between the boron and metal atoms in the hexaborides is weak. Therefore, we can regard divalent-metal hexaborides such as CaB₆ as “ionic crystals” which can be expressed approximately as M²⁺(B₆)^2?. At the same time, trivalent-metal hexaborides such as YB₆ are thought to be metals in which the conduction electron concentration is one per unit cell.