Universität zu Köln

Bubeck, Sascha (2022). Implementation and Application of the Core Polarization Potential Ansatz in Quantum Chemical Systems. PhD thesis, Universität zu Köln.

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Abstract

Modern quantum chemical simulations are computationally demanding and one approach to reduce these demands is the pseudopotential ansatz. This ansatz, however, approximates the interaction of the valence and core electrons in a way that neglects the polarizability of the atomic core. While the core polarization potential (CPP) ansatz addresses this neglected polarization, exhaustive studies of its influence in molecular simulations are still scarce. Here, we present a customized implementation of the CPP ansatz to establish an entry point for such studies in the Quantum Objects Library, a program package of the Institute for Theoretical Chemistry (University of Cologne). We successfully tested the implementation in atomic and molecular systems, both on the Hartree-Fock and the electron-correlation level. Additionally, we investigated the influence of CPPs in two systems - Hg2 and HgF4 - employing scalar-relativistic small-core pseudopotentials for mercury. For this, we developed a new approach for generating CPPs relying purely on ab initio data. The influence of the generated CPPs on the molecular properties of the investigated systems was small and requires a more detailed nvestigation.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Bubeck, Sascha UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-635594
Date:	2022
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Theoretical Chemistry
Subjects:	Natural sciences and mathematics
Uncontrolled Keywords:	Keywords Language core polarization potentials English quantum chemistry UNSPECIFIED mercury UNSPECIFIED
Date of oral exam:	7 December 2021
Referee:	Name Academic Title Dolg, Michael Prof. Dr. Hanrath, Michael Dr.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/63559