Valence electron bands in the gas-phase x-ray photoelectron spectra of acetonitrile and nitromethane

The valence electron bands of the gas-phase X-ray photoelectron spectra were measured on acetonitrile and nitromethane. It is shown that the observed spectra can be interpreted successfully by comparison with the He I photoelectron spectra and the results of CNDO/2 calculations.     

Simulation of x-ray absorption near-edge spectra and x-ray fluorescence spectra of optically excited molecules

The x-ray absorption near-edge spectra (XANES) and fluorescence spectra of molecules in the ground state and optically excited states are computed using time-dependent density functional theory and time-dependent Hartree-Fock theory. The calculated XANES spectra of optically excited methanol, benzonitrile, hydrogen sulphide, and titanium tetrachloride and the fluorescence spectra of optically excited methanol can be used to simulate ultrafast optical pump/x-ray probe experiments.     

Program DEIMOS32 for gamma-ray spectra evaluation

The main features of a program for gamma-ray spectra analysis in the Windows environment are described. The program allows handling of HPGe multichannel pulse-height spectra produced by many commercial instruments. It performs the analysis using an interactive manual or automatic mode of evaluation. Results are directed to a number of different output files. The performance of the evaluation can be affected by selecting only regions with prescribed type of peaks. The calibration of the detector efficiency is included. Identification of isotopes and the calculation of their absolute activities are possible. Data can be edited in an internal text editor.     

K x-ray emission spectra from natural silicates

Chemical shifts of Si Kα_1,2 and Al Kα_1,2 lines in seven natural silicates has been measured comparatively to the lines of the pure elements. An attempt is made to correlate these shifts to the surroundings of Si and Al in the minerals.     

pH-dependent x-ray absorption spectra of aqueous boron oxides

Near edge x-ray absorption fine structure (NEXAFS) spectra at the boron K-edge were measured for aqueous boric acid, borate, and polyborate ions, using liquid microjet technology, and compared with simulated spectra calculated from first principles density functional theory in the excited electron and core hole (XCH) approximation. Thermal motion in both hydrated and isolated molecules was incorporated into the calculations by sampling trajectories from quantum mechanics∕molecular mechanics simulations at the experimental temperature. The boron oxide molecules exhibit little spectral change upon hydration, relative to mineral samples. Simulations reveal that water is arranged nearly isotropically around boric acid and sodium borate, but the calculations also indicate that the boron K-edge NEXAFS spectra are insensitive to hydrogen bonding, molecular environment, or salt interactions.     

Dependence of muonic x-ray intensity spectra and bond ionicities

It is shown that the muonicK /K intensity ratios in oxygen of oxides of third-row elements are correlated to the bond ionicities. A similar correlation is found in chlorine of corresponding compounds. These correlations confirm the dominant role played by the outer electrons of the bond partners in the coulomb capture mechanism of negative muons.     

Biasing effect of non-conductive solids in x-ray photoelectron spectra

The effect of biasing the sample holder was investigated in a range of ?300 to +300 V, in order to study the surface charging of non-conductive samples. Shifts in kinetic energies of photoelectron and peak broadening were compared to the dielectric constants and the volume resistivity of the solid.     

Soft electron (low energy electron) processing of foods for microbial control

“Soft-electron” is a new term we have created referring to electrons with energies of 300 kV or lower. Homogenous irradiation of surfaces with soft electrons can decontaminate dry food ingredients such as gains, pulses, spices, dehydrated vegetables and tealeaves without detrimental effects. Treatment of soybeans with electrons of acceleration voltages at 170 kV reduced their microbial count to an undetectable level. Pre-treatment of soybeans with soft electrons enabled the extension of soymilk without sterilization process at a high temperature (120°C). The gelatinized property of soymilk from soft electron-treated beans was better than that of high-temperature sterilized soymilks. These results indicate that soft-electron sterilization improved the quality of soybeans for the processing of soymilk and Tofu(soymilk curd).