Analysis of x-ray spectra emitted by highly charged ions in an electron-cyclotron-resonance ion source (ECRIS) may be used as a tool to estimate the charge-state distribution (CSD) in the source plasma. For that purpose, knowledge of the electron energy distribution in the plasma, as well as the most important processes leading to the creation and de-excitation of ionic excited states are needed. In this work we present a method to estimate the ion CSD in an ECRIS through the analysis of the x-ray spectra emitted by the plasma. The method is applied to the analysis of a sulfur ECRIS plasma.
Benzyl azide and the three methylbenzyl azides were synthesized and characterized by mass spectrometry (MS) and ultraviolet photoelectron spectroscopy (UVPES). The electron ionization fragmentation mechanisms for benzyl azide and their methyl derivatives were studied by accurate mass measurements and linked scans at constant B/E. For benzyl azide, in order to clarify the fragmentation mechanism, labelling experiments were performed. From the mass analysis of methylbenzyl azides isomers it was possible to differentiate the isomers ortho, meta and para. The abundance and nature of the ions resulting from the molecular ion fragmentation, for the three distinct isomers of substituted benzyl azides, were rationalized in terms of the electronic properties of the substituent. Concerning the para-isomer, IRC calculations were performed at UHF/6-31G(d) level. The photoionization study of benzyl azide, with He(I) radiation, revealed five bands in the 8-21 eV ionization energies region. From every photoelectron spectrum of methylbenzyl azides isomers it has been identified seven bands, on the same range as the benzyl azide. Interpretation of the photoelectron spectra was accomplished applying Koopmans' theorem to the SCF orbital energies obtained at HF/6-311++G(d, p) level.
A new approach is laid out to investigate two-photon atomic transitions. It is based on the application of the finite-basis solutions constructed from the Bernstein polynomial (B-polynomial) sets. We show that such an approach provides a very promising route for the relativistic second-order (and even higher-order) calculations since it allows for analytical evaluation of the involved matrices elements. In order to illustrate possible applications of the method and to verify its accuracy, detailed calculations are performed for the 2 s 1/2 ‚Üí 1 s 1/2 transition in neutral hydrogen and hydrogen-like ions, which are compared with the theoretical predictions based on the well-established B-spline basis-set approach.
Ionization energies of benzyl azide (BA), C6H5CH2N3, its methyl derivatives, 2-, 3- and 4-methyl benzyl azide and (1-azidoethyl)benzene (2-, 3- and 4-MBA and 1-AEB), (CH3)C6H4CH2 N3, have been calculated with several basis sets, with M¯ller-Plesset and Hartree-Fock methods. The data are compared to the ionizations energies obtained from HeI photoelectron spectroscopy (UVPES) experiments, in order to support the correct assignment of the bands. The nature and character of the molecular orbitals are also discussed.
