Results 1 - 10 of 34784
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[en] This paper presents Auger electron spectroscopy with a retarding field analyser designed for an advanced physics experiment carried out in 'Physics Laboratory II' at the Institute of Experimental Physics, University of Wroclaw, Poland. The authors discuss the process of setting up the experiment and the results of the measurement of Auger spectra. The advantages and disadvantages of the apparatus are discussed along with its implementation in the teaching process
[en] Variation trends across the AnO2 series of An5f-electron covalent bonding and An5f→O3s, O2p→An5f charge transfer energies, are studied using DV-Xα relativistic spin-polarised computation of electronic structures applied to 11 'AnO8' clusters, from ThO8 to FmO8. It is found that the binding energies of 5f orbitals, therefore the An5f-O2p hybridisation, are increasing though the 5f orbitals are localising across the An series. In our calculations, the 3s and 3p ionic-like orbitals of O2- ions are included for the first time as LCAO-MO bases. Then, the conduction band is a mixing of O3s and An6d and its lower edge corresponds to an O3s-dominated state. Moreover, the calculated charge transfer (CT) energies of An5f→O3s and O2p→An5f transitions show the so-called tetrad effect when CT energies, respectively increasing and decreasing across the AnO2 series. It is pointed out that the tetrad effect here comes mainly from the special spin-polarised pattern of 5f levels and the increasing general trend of 5f binding energies. (orig.)
[en] We investigated the Autler–Townes splitting in photoelectron spectra of molecules steered by ultrashort laser pulses using the time-dependent wave-packet method. Structure of the Autler–Townes splitting was presented to analyze the information of a selective population of the dressed states. It was found that population transfer process, structure of photoelectron spectrum and pattern of Autler–Townes splitting can be controlled by adjusting the intensity, wavelength and delay time of laser pulses. (paper)
[en] We show how to extract the energy- and coordinate dependence of dipole-moments for a neutral-to-ionic molecular transition from time-resolved photoelectron spectra. The procedure needs the potential surfaces of the neutral and the cationic state which are involved in the ionization process as an input. Given these potentials and the laser parameters it is possible to determine the functional form of the transition dipole moment from the measured time- and energy-resolved transient signals. (authors)
[en] Calibration is required to obtain analyte concentrations in atomic spectrometry. To take full benefit of it, the adequacy of the coefficient of determination r2 is discussed, and its use is compared with the uncertainty due to the prediction bands of the regression. Also discussed from a tutorial point of view are the influence of the weighting procedure and of different weighting factors, and the comparison between linear and quadratic regression to cope with curvatures. They are illustrated with examples based on the use of ICP-AES with nebulization and laser ablation, and of LIBS. Use of a calibration graph over several orders of magnitude may be problematic as well as the use of a quadratic regression to cope with possible curvatures. Instrument softwares that allow reprocessing of the calibration by selecting standards around the expected analyte concentration are convenient for optimizing the calibration procedure.