Pulsed Laser Sputtering Research Articles

Multilayer TiBe interference structures for ultrasoft X-ray radiation prepared by pulsed laser sputtering

This paper is concerned with the properties of multilayer TiBe interference structures in the ultrasoft X-ray region. The structures were prepared by pulsed laser sputtering with a radiation power density at the target Q= 0.2−1 GW/cm 2. It is shown that the angular dependences of the reflection coefficients measured at wavelengths λ = 114 A ̊ ( Be K α ) and λ = 1.54 A ̊ ( Cu K α ) are described well by the theoretical dependences calculated using the atomic scattering factors from ref. [2]. The value of the reflection coefficient reaches 40% at λ = 114 A ̊ .

Neon matrix ESR and CI theoretical investigation of 1BF+ and 11BF+: Photoionization of BF from reactive laser sputtering and high temperature sources

The 11BF+ and 10BF+ radical cations have been generated and trapped in neon matrices at 4 K using the combined techniques of pulsed reactive laser sputtering and photoionization at 16.8 eV. An independent high temperature source of BF(g) in conjunction with photoionization was also employed and a comparison between these two different generation methods reveals no significant differences in their ESR spectra. The magnetic parameters for 11BF+ measured in neon matrices are g∥=2.0012(3), g⊥=2.0004(3), (11B) A∥=1784(1), and A⊥=1727(1) MHz, (19F)A∥=410(1), and A⊥=152(1) MHz. Extensive ab initio theoretical calculations have been conducted for BF+ and the nuclear hyperfine properties obtained from various types of CI wave functions show excellent agreement with the experimental measurements. Valence orbital occupancies obtained from a Mulliken-type population analysis performed on the CI wave functions are compared with the conventional free atom comparison method for obtaining electronic structure information from ESR A tensor measurements. The distribution of the unpaired electron in BF+ is compared to six other isoelectronic first row radicals.

Ultra high vacuum aspects of the investigation of surface phenomena

The investigation of surface structures and phenomena by such techniques as low energy electron diffraction and high energy electron diffraction has become possible in the last years thanks to the development of pumping and measuring devices able to produce and monitor vacua of the order of 10 −12 torr. At these pressures, surfaces can be kept clean for as long as a few hours; in this way it is possible to investigate clean surface structures and surface phenomena such as adsorption-desorption with a minimum of trouble due to the presence of residual gases. The problem of degassing is discussed in detail. Particular attention is paid to the problem of the generation of clean surfaces by pulsed laser bombardment, sputtering and annealing. The characterization of the degree of cleanliness of surfaces is treated and reference is made in some detail to those methods based on electromagnetic interactions of radiation with matter: Auger Electron Spectroscopy, Electron Spectroscopy for Chemical Analysis (ESCA), Characteristic X-ray Spectroscopy.