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X-ray resonant Raman scattering Spectra simulation from first principles for Copper below the ionization threshold using high-performance computing

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Detalhes bibliográficos
Resumo:The work performed on this thesis comes as part of the effort to further understand the highly convoluted structure present on Copper’s x-ray emission spectra, where, as with many other transition metals, a skewness can be observed on the K1 and K2 x-ray transition lines. These lines originate due to the radiative relaxation of the atom’s electronic structure post-ionization of inner shell electrons. One of the possible explanations for the observed skewness are Copper’s radiative transitions originating from its satellite states. Throughout this thesis, a study will be performed for the satellite states formed by the excitation of the inner-shell electrons, where a photoexcitation process occurs, as opposed to the ionization process that is usually considered in x-ray calculations, and all the consecutive radiative decay possibilities. Multiple atomic structure calculations will be performed using the ab initio state-ofthe- art Multiconfiguration Dirac-Fock General Matrix Elements (MCDFGME) code for different excited states configurations. The obtained results can then be used in the analysis of experimental data obtained with a High-Precision Double Crystal Spectrometer (DCS), using a synchrotron x-ray source. Due to the complexity of the calculations, the process can become substantial in terms of computational power and time. Therefore, a parallelized calculation deploying code, employing a Message Passing Interface (MPI) protocol and High Performance Computing, will be written as to be able to perform similar but more complex calculations using a supercomputer, such as the one in the University of Évora (OBLIVION).
Autores principais:Baptista, Gonçalo Garcês Sobreira Rodrigues
Assunto:Radiative relaxation x-ray transition lines photoexcitation MCDFGME DCS High Performance Computing
Ano:2023
País:Portugal
Tipo de documento:dissertação de mestrado
Tipo de acesso:acesso aberto
Instituição associada:Universidade Nova de Lisboa
Idioma:inglês
Origem:Repositório Institucional da UNL
Descrição
Resumo:The work performed on this thesis comes as part of the effort to further understand the highly convoluted structure present on Copper’s x-ray emission spectra, where, as with many other transition metals, a skewness can be observed on the K1 and K2 x-ray transition lines. These lines originate due to the radiative relaxation of the atom’s electronic structure post-ionization of inner shell electrons. One of the possible explanations for the observed skewness are Copper’s radiative transitions originating from its satellite states. Throughout this thesis, a study will be performed for the satellite states formed by the excitation of the inner-shell electrons, where a photoexcitation process occurs, as opposed to the ionization process that is usually considered in x-ray calculations, and all the consecutive radiative decay possibilities. Multiple atomic structure calculations will be performed using the ab initio state-ofthe- art Multiconfiguration Dirac-Fock General Matrix Elements (MCDFGME) code for different excited states configurations. The obtained results can then be used in the analysis of experimental data obtained with a High-Precision Double Crystal Spectrometer (DCS), using a synchrotron x-ray source. Due to the complexity of the calculations, the process can become substantial in terms of computational power and time. Therefore, a parallelized calculation deploying code, employing a Message Passing Interface (MPI) protocol and High Performance Computing, will be written as to be able to perform similar but more complex calculations using a supercomputer, such as the one in the University of Évora (OBLIVION).