A Numerical Approach to the Accurate Calculation of Atomic and Molecular Properties

Stewart, Ronald F (1973) A Numerical Approach to the Accurate Calculation of Atomic and Molecular Properties. PhD thesis, University of Glasgow.

Abstract

An attempt is made to demonstrate that simple numerical methods can be used to advantage in the accurate calculation of atomic and molecular properties. In the early part of the thesis finite-difference techniques are employed in conjunction with conventional variational methods to calculate accurately the correlation energies of small atoms within a variety of perturbation schemes. Of particular interest is a thorough investigation of Hartree-Fock perturbation theory through third order for the Be isoeleotronic sequence Li- -- Ne6+ with about a 90% recovery of Ecorr. Numerical methods are also used to examine the efficacy of the single-centre approach to the calculation of the electronic structures of simple molecules in their ground and excited states, the high accuracy of the computational scheme employed allowing some insight into the frequently observed slow convergence of the one-centre method. The efficiency of numerical techniques in the determination of atomic and molecular properties is further shown by studies on the non-empirical evaluation of atomic polarisabilities (static and dynamic) and of interatomic dispersion forces. Notably a new method of computing Van der Waals coefficients of considerable elegance and economy is presented. In the final section of the work the numerical computational techniques developed in non-empirical calculations of pair correlation energies, polarisabilities, dispersion coefficients in small systems are applied to much larger atoms within a model potential framework. All of the above properties are determined for a wide variety of systems with however the alkali metals and their anions being the subject of the most comprehensive treatment.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Computational chemistry, Physical chemistry, Molecular chemistry
• Date of Award: 1973
• Depositing User: Enlighten Team
• Unique ID: glathesis:1973-78638
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 28 Feb 2020 12:09
• Last Modified: 28 Feb 2020 12:09
• URI: https://theses.gla.ac.uk/id/eprint/78638