ATOMIC STUCTURE CALCULATIONS AND PROCESSES IN HIGHLY CHARGED IONS

Abstract

Atomic Structure Calculations and processes in highly charged ions Atomic Structure Calculations with parameters for highly charged ions have been investigated theoretically and experimentally.In our work, we presented complete spectroscopic data, comprehensive data and elaborate study along with a detailed theoretical investigation of C-like W (WLXIX), K-like W (W LVI), Na-like K (KIX), Na- like W (W LXIV) ions, based on the fully relativistic multi-configuration Dirac-Fock (MCDF) method. We included QED (quantum electrodynamics) corrections due to vacuum polarization and self-energy effects as well as Breit correction due to the exchange of virtual photons between two electrons are fully considered in our calculations. We have determined the energy levels and radiative data for multiple transitions such as electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2) and identified soft X-ray transitions (SXR) and hard X-ray (HXR) transitions from highly excited states to ground state. Furthermore, we have also provided relative population for the first five excited states, with both the partition function and thermodynamic quantities and studied their variations with temperature. The significance of valence valence (VV) and core valence (CV) correlations, along with their effects, have been discussed as well as the influence of plasma temperature (range between 2 ⨯ 106 to 1 ⨯ 1010 K) on line intensity ratio with the number of electron density has been studied for Hot dense plasma (HDP). The credibility and authenticity of our furnished results, related calculations have also been performed using another independent fully relativistic configuration interaction program, which is FAC (Flexible Atomic Code) based on self- consistent Dirac-Fock-Slater iteration method. The configuration interaction technique (CIV3) have also been done to confirm the accuracy of energy levels for particular ion (KIX). Atomic data including energies, transition wavelengths, radiative rates, oscillator strengths, are evaluated for these ions. Furthermore, we have analyzed the photoionization cross section and ionization potential of 3s, 3p and 3d levels at five different photoelectron energies by employing the FAC code.We also compared our computed energies with experimental energy levels compiled by NIST and other available theoretical or experimental data in the literature and there are a few minor differences discussed. Our newly reported atomic data and radiative data will help to analyze the spectral lines obtained from various diagnoses of solar, useful in astrophysical research and fusion vi plasma sources. Our data will also be beneficial for plasma modelling, cell biology, biophysics and their applications. The results of our research have been divided into six chapters with the following chapter- by-chapter brief details as; Chapter 1, offers a concise introduction about the importance of atomic structure process, importance of atomic structure of ion and the importance of highly chared ion of atomic data in fusion plasma and discuss the most commonly used methods developed for the production of atomic spectroscopic data. We briefly review the techniques that have been used in the calculation of photoionization cross section and significance of photoionization.The several experimental techniques and theoretical methods which have been developed for the production of atomic data. A brief review and atomic structure calculations for one electron system, two electron system, multi electron system, central field approximation and Configuration Interaction including relativistic effects are described. Chapter 2, we have represented the complete spectroscopic data and a detailed theoretical investigation of C-like W (WLXIX) utilizing the multi-configuration Dirac-Fock (MCDF) technique, which is fully relativistic. Two corrections: quantum electrodynamics (QED) which is related with vacuum polarisation and self-energy effects, as well as Breit which is related towards the exchange of virtual photons among two electrons. For the lowest 205 fine structure levels, we presented energy levels and radiative data for various transitions such as electric dipole (E1), electric quadrupole (E2) as well as magnetic dipole (M1), magnetic quadrupole (M2) and identified soft X-ray transitions (SXR) and hard X- ray (HXR) transitions from highly excited states to ground state have been predicted. The credibility and authenticity of our furnished results, we also used a Flexible Atomic Code (FAC), based on self-consistent Dirac-Fock-Slater iteration approach, which is fully independent relativistic configuration interaction system. The two independent atomic- structure analysis shows a reasonably good agreement. Computed energies to experimental energy levels is compiled by NIST. The intensity spectra for transitions decaying to ground state for W LXIX. Atomic and radiative data of C-like W will help identify and analyze spectral lines obtained from various diagnoses of solar, fusion plasma research as well as astrophysical exploration. vii Chapter 3, we have included the complete spectroscopic data and a detailed theoretical investigation of tungsten and K-like W (WLVI) based on the fully relativistic multi- configuration Dirac-Fock (MCDF) method. Relativistic corrections, QED (Quantum electrodynamics) and Breit corrections in our computation. Energy levels and radiative data for multipole transitions i.e. electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1)and magnetic quadrupole (M2) within lowest 142 fine structure levels and predicted soft x-ray transition (SXR) and extreme ultraviolet transitions (EUV) from higher excited states to ground state. Data with energy levels compiled by NIST and other available results in literature and small discrepancies found with them are discussed. Furthermore, the relative population for first five excited states, partition function and thermodynamic quantities for both W LVI and studied their variations with temperature have also presented. New atomic data of W LVI, which are discussed in chapter 3 may be useful in identification and analysis of spectral lines from various astrophysical and fusion plasma sources and also beneficial in plasma modeling. Chapter 4, we have signified the importance and effect of valence valence (VV) and core valence (CV) correlations on the excitation energies have been discussed in graphical and tabular form for KIX. In this chapter. By utilizing MCDF method for KIX and W LXVI calculations, included the contribution of QED and Breit relativistic corrections and concluded that the effect of QED corrections. The large-scale configuration interaction technique (CIV3) have also been done to confirm the accuracy of energy levels for KIX. For W LXIV, 21 in Electric dipole, 33 in Electric quadrupole, 28 in Magnetic dipole and 21 in Magnetic quadrupole Soft x-ray (SXR) transitions as well as 1 in Electric dipole Extreme Ultraviolet (EUV) transitions identified from ground state. The calculated results are in close agreement with NIST compiled data and other available results. The influence of plasma temperature (2 ⨯ 106 to 1 ⨯ 1010 K) on line intensity ratio with the number of electron density has been studied for the hot dense plasma (HDP) graph for KIX. KIX and WLXIV results are valuable or beneficial for the characterization of HDP, astrophysical plasmas, plasma modelling, cell biology, biophysics, fusion plasma research as well as astrophysical studies and their applications. Chapter 5, we have discussed the atomic data including energies, transition wavelengths, radiative rates, oscillator strengths, are evaluated for W LXIV, for the lowest 100 fine structure levels and multipole transitions(E1, E2, M1 and also for M2). For W LXIV, we viii identified the 21 in electric dipole, 33 in electric quadrupole, 28 in magnetic dipole and 21 in magnetic quadrupole soft x-ray (SXR) transitions, as well as 1 in electric dipole extreme ultraviolet (EUV) transitions from the ground state. Furthermore, we have analyzed the photoionization cross section and ionization potential of 3s, 3p and 3d levels of Na-like W at five different photoelectron energies by employing the FAC code. Line intensity ratios and electron density for W LXIV have also been reported, which will be useful and necessary for plasma diagnostics, including modelling for future International Thermonuclear Experimental Reactor (ITER) investigations. We assume that our observations will be useful for cell biology, biophysics, fusion plasma research, as well as astrophysical studies and their applications. Chapter 6, indicates that the thesis conclusion with a summary, a brief recapitulation of the research presented in previous chapters, social impact and possible future approaches for extending work addressed. References also form part along with bibliography at the end of each chapter.