During polar-cap absorption events, which are caused by the incidence of energetic solar protons, the highlatitude ionospheric D region is extended down to relatively low altitudes. While the incoming proton fluxes may be monitored by satellite-borne detectors, and the resulting radiowave absorption with a ground-based riometer, the enhancement of electron density at a given altitude is less ea...

The effects of energetic electron precipitation into the auroral region at a time of enhanced solar wind have been investigated during a continuous period of 24 h, using the European Incoherent Scatter (EISCAT) radar, an imaging riometer, and particle measurements on an orbiting satellite. The relative effects in the E region (120 km) and D region (90 km) are found to vary during the day, consi...

A resonance behaviour of the far infrared absorption probability at a frequency∼ N1/4 is predicted for clusters of N electron-hole pairs (2 ≤ N ≤ 110) confined in disk-shaped quantum dots. For radially symmetric dots, the absorption is dominated by a Giant Dipole Resonance, which accounts for more than 98 % of the energy-weighted photoabsorption sum rule. PACS numbers: 71.35.Ee, 78.66.-w

A 9-phenylanthracene, constrained in a coplanar fashion by two methylene tethers, was synthesized and its optoelectronic properties were investigated. The rigid planarization increased its electron-donating character and induced a bathochromic shift of its absorption, as well as an increased molar absorption coefficient and intense fluorescence. These properties render this compound a promising...

Transient absorption spectroscopy was used to study light induced electron transfer processes in Type 1 photosynthetic reaction centers. Flash induced absorption changes were probed at 800, 703 and 487 nm, and on multiple timescales from nanoseconds to tens of milliseconds. Both wild type and menB mutant photosystem I reaction centers from the cyanobacterium Synechocystis sp. PCC 6803 were stud...

Thin films of copper indium diselenide (CIS) were prepared by chemical bath deposition technique onto glass substrate at 60C. The studies on composition, morphology, optical absorption, electrical conductivity and structure of the films were carried out. Characterization includes X-ray diffraction (XRD), Scanning electron microscopy (SEM), Atomic force microscopy (AFM), Energy dispersive x-ray ...

We have used a multi-particle imaging technique (COLTRIMS) to observe the double ionization of rare gas atoms by multi-photon absorption of 800 nm (1.5 eV) femto-second laser pulses and by single photon absorption (synchrotron radiation). Both processes are mediated by electron correlation. We discuss similarities and differences in the three-body final state momentum distributions.

In gauge theory of gravity, there is direct coupling between the spin of a particle and gravitomagnetic field. In the surface of a neutron star or near black hole, the coupling energy between spin and gravitomagnetic field can be large and detectable. Precise measurement of the position of spectrum lines of the corresponding emission or absorption can help us to determine the gravitomagnetic fi...

We calculate the transition rates between proton Landau levels due to non-radiative and radiative Coulomb collisions in an electron-proton plasma with strong magnetic field B. Both electron-proton collisions and proton-proton collisions are considered. The roles of the first-order cyclotron absorption and second-order free-free absorption and scattering in determining the line strength and shap...

We propose an architecture of conformal metal-semiconductor-metal (MSM) device for hot-electron photodetection by asymmetrical alignment of the semiconductor barrier relative to the Fermi level of metals and strong energy localization through plasmonic resonances. Compared with the conventional grating design, the multi-layered grating system under conformal configuration is demonstrated to pos...