Accurate Born-Oppenheimer Molecular Calculation with Explicitly Correlated Gaussian Function

Persistent Link:
http://hdl.handle.net/10150/265398
Title:
Accurate Born-Oppenheimer Molecular Calculation with Explicitly Correlated Gaussian Function
Author:
Tung, Wei-Cheng
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The research over-viewed in this dissertation concerns very accurate variational calculations of the molecular systems with more than two electrons under the assumption of the Born-Oppenheimer (BO) approximation. The centerpiece of this research is the use of explicitly correlated Gaussian (ECG) basis functions with floating centers to generate the potential energy curve (PEC) and potential energy surface (PES) of the considered molecular systems. One challenge of such calculations is the occurrence of the linear dependency between basis functions in the process of basis set optimization. The BO PECs generated with ECG basis sets were limited to two-electron molecular systems for a few decades prior to the implementation of the author's approaches to this issue. These approaches include methods for a partial remedy to linear dependence, better guessing of initial basis functions, permanently removing the restriction of memory usage in parallel computer systems, and efficiently paralleling the calculations. The approach effectively utilizing the super computer systems yields benefits not only to the ECG calculations but could also be useful in the fields that require the significant amount of the computational resources. These procedures were implemented in computer codes that were run quite extensively on several parallel computer systems during the period of the author's Ph.D study. The calculated adiabatic PECs and the rovibrational energy levels are proven to be the most accurate ones to date. The dissertation is primarily based on the content of the papers that were published in co-authorship with my scientific advisor and other collaborators in several scientific journals. It also includes some details that were not considered in the publications but are essential for the completeness and good understanding of the presented work. In order to provide readers an insight into the development of the ECG based BO molecular calculation, the published results of many calculations are classified and presented in a comprehensive way.
Type:
text; Electronic Dissertation
Keywords:
ECG; Chemistry; BO; Born-Oppenheimer
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Chemistry
Degree Grantor:
University of Arizona
Advisor:
Adamowicz, Ludwik

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleAccurate Born-Oppenheimer Molecular Calculation with Explicitly Correlated Gaussian Functionen_US
dc.creatorTung, Wei-Chengen_US
dc.contributor.authorTung, Wei-Chengen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe research over-viewed in this dissertation concerns very accurate variational calculations of the molecular systems with more than two electrons under the assumption of the Born-Oppenheimer (BO) approximation. The centerpiece of this research is the use of explicitly correlated Gaussian (ECG) basis functions with floating centers to generate the potential energy curve (PEC) and potential energy surface (PES) of the considered molecular systems. One challenge of such calculations is the occurrence of the linear dependency between basis functions in the process of basis set optimization. The BO PECs generated with ECG basis sets were limited to two-electron molecular systems for a few decades prior to the implementation of the author's approaches to this issue. These approaches include methods for a partial remedy to linear dependence, better guessing of initial basis functions, permanently removing the restriction of memory usage in parallel computer systems, and efficiently paralleling the calculations. The approach effectively utilizing the super computer systems yields benefits not only to the ECG calculations but could also be useful in the fields that require the significant amount of the computational resources. These procedures were implemented in computer codes that were run quite extensively on several parallel computer systems during the period of the author's Ph.D study. The calculated adiabatic PECs and the rovibrational energy levels are proven to be the most accurate ones to date. The dissertation is primarily based on the content of the papers that were published in co-authorship with my scientific advisor and other collaborators in several scientific journals. It also includes some details that were not considered in the publications but are essential for the completeness and good understanding of the presented work. In order to provide readers an insight into the development of the ECG based BO molecular calculation, the published results of many calculations are classified and presented in a comprehensive way.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectECGen_US
dc.subjectChemistryen_US
dc.subjectBOen_US
dc.subjectBorn-Oppenheimeren_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorAdamowicz, Ludwiken_US
dc.contributor.committeememberSanov, Andreien_US
dc.contributor.committeememberSchwartz, Stevenen_US
dc.contributor.committeememberMash, Eugeneen_US
dc.contributor.committeememberAdamowicz, Ludwiken_US
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