We report on in situ studies of the vibrational properties of ultra-thin Si layers grown by dc magnetron sputtering in ultrahigh vacuum on amorphous MgO and Ag buffer layers. The average thickness of the Si layers ranged from monolayer coverage up to 200 Ǻ. The interference enhanced Raman scattering technique has been used to study changes in the phonon spectra of Si nanoparticles during the cr...

A spinel ferrite of the system NiSixFe2-xO4 with (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were studied via IR, Xray spectra and cation distribution. The X-ray pattern confirmed the spinel cubic structure of all Si contents. The lattice parameters estimated as a function of Si contents indicated a slight decrease of lattice parameter up to 0.2. The grain size increases with increasing Si content up t...

We report the first experimental results on angle-resolved elastic light scattering in the soft X-ray regime, where free sub-micron particles in the size regime between 150 and 250 nm are studied in the gas phase by using a continuous particle beam. Two different types of studies are reported: (i) Angle-resolved elastic light scattering experiments provide specific information on the scattering...

Based on our previous work on the recursive fermion system in the Cuntz algebra, it is shown that a nonlinear transformation group of the CAR fermion algebra is induced from a U(2) action on the Cuntz algebra O2p with an arbitrary positive integer p. In general, these nonlinear transformations are expressed in terms of finite polynomials in generators. Some Bogoliubov transformations are involv...

We investigate the production of Si 2p Auger electrons during bombardment of Si surfaces by 1.0-5.1 keV Ar+ ions. Yields of Auger electrons emitted at 146 a with respect to the ion beam are measured as a function of ion energy. We observe a threshold of 3.8 keV for formation of a double L vacancy in Si, which is due to Ar-Si collisions. This value is higher than those of previous studies, which...

Reproducible time-of-flight cluster static secondary ion mass spectra (ToF-SSIMS) were obtained for various standard calcium phosphate (CP) powders, which allowed for phase identification. X-ray diffraction was not able to detect signals from microscopic amounts of CP (∼15 mmol m(-)(2)). The phases studied were α-tricalcium phosphate [α-Ca(3)(PO(4))(2)], β-tricalcium phosphate [β-Ca(3)(PO(4))(2...

We report the calculation of the UV spectra of more than 40 substituted coumarins and chromones in solution. In particular, two solvent models are compared, the multipolar expansion model (NCM) developed in Nancy and the PCM scheme developed in Pisa and Napoli. All calculations are carried out at the NCM-TDPBE0/6-311G(2d,2p)//NCM-B3LYP/6-311G(2d,2p) and at the PCMTDDFT/6-311+G(2d,2p)//PCM-DFT/6...

The crystal structure and chemical bonding of magnetron-sputtering deposited nickel carbide Ni₁-xCx (0.05 ⩽ x⩽0.62) thin films have been investigated by high-resolution x-ray diffraction, transmission electron microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, and soft x-ray absorption spectroscopy. By using x-ray as well as electron diffraction, we found carbon-containing hcp-Ni...

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different...

By combining multiple electron coincidence detection with ionization by synchrotron radiation, we have obtained resolved spectra of the OCS(3+) ion created through the double Auger effect. The form of the spectra depends critically on the identity of the atom bearing the initial hole. High and intermediate level electron structure calculations lead to an assignment of the resolved spectrum from...