Revisited Relativistic Dirac-Hartree-Fock X-ray Scattering Factors for Neutral Atoms with Z = 2 – 118, and Chemically-Relevant Ions: All Cations, Selected Monovalent Anions, and the Excited (Valence) States of Carbon & Silicon.

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Shiroye, Olukayode oloyede
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Middle Tennessee State University
This is a two-article dissertation structure which comprises of four chapters. Chapter one gives the general overview of the research interest, motivation and identified gaps in the literature. The chapter two and three compose of the first and second papers submitted for publication respectively. Chapter four discussed the conclusion drawn on the results obtained from the research and how this result compares to previous studies on X-ray scattering factor calculation. For this dissertation, two papers have been submitted for publications on revisited relativistic Dirac-Hartree-Fock X-ray scattering factor for neutral atoms with Z = 2 – 118 (He – Og) and Chemically-Relevant Ions: All Cations, Selected Monovalent Anions, and the Excited (Valence) States of Carbon & Silicon. The X-ray scattering factor calculation used the recently developed DBSR_HF program [Zatsarinny & Froese Fischer (2016). Comput. Phys. Comm. 202, 287 – 303] to calculate the fully relativistic Dirac-Hartree-Fock ground-state wavefunctions for all atoms with Z = 2 – 118 (He – Og) and 318 chemically relevant ions. The calculations use the extended average level scheme and include both the Breit interaction correction to the electronic motion due to magnetic and retardation effects, and the Fermi distribution function for the description of the nuclear charge density. Using the total and orbital (spinor) energies, charge density maxima, atomic mean radii and means spherical radii (Guerra et al., 2017) for the neutral atoms and total electronic & ionization energies for ions, adequate comparison have been made between the results obtained and several previous studies. A newly developed Fortran program SF was used for a precise integration of the X-ray scattering factors by employing the DBSR_HF’s B-spline representation of the relativistic oneelectron orbitals. Interpolation of the obtained X-ray scattering factor has also been done in the v 0 ≤ sin ? /? ≤ 2 Å −1 and 2 ≤ sin ? /? ≤ 6 Å −1 ranges using the recommended analytical functions for a four-term and five-term expansions. The X-ray scattering factor values obtained from the uniform treatments of the all the species seem to represent an excellent compromise among all the previous studies and should be a good replacement for values in Volume C of the 2006 edition of International Table for Crystallography (Maslen, Fox & O’Keefe, 2006).
Computational chemistry