Kairalapova, Arailym
(2020)
Theoretical Approaches for Studying Non-Valence Correlation-Bound and Correlation-Assisted Anion States of Molecules and Molecular Clusters.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
This is the latest version of this item.
Abstract
Non-valence correlation-bound and correlation-assisted anion states of molecules and molecular clusters have been characterized using various electronic structure methods. In these species long-range dispersion type correlation interactions are responsible for binding of the excess electron in a spatially diffuse orbital. Therefore, the Hartree-Fock method and methods that depend on the Hartree-Fock wave function being a suitable reference fail to bind such anions or greatly underestimate the electron binding energy. The main approach used in the present studies is the equation of motion coupled-cluster method. Additional methods may also accurately describe these non-valence anions provided adequate orbital relaxation in response to long-range dispersion-like correlation effects is included. Non-valence correlation- bound anion states of a model (H2O)4 cluster, the bent CO2, and tetracyanoethylene are characterized.
In addition to bound non-valence anions, some species may possess temporary anion states that lie energetically above the ground state of the neutral molecule and, thus, are subject to electron autodetachment. These temporary anion shape resonances are trapped by a potential barrier and are characterized by a complex energy. The temporary anion shape resonances of the model (H2O)4 cluster and rhombic (NaCl)2 are described. In case of (H2O)4 cluster, the shape resonance corresponds to an asymmetric combination of the dipole-bound anion states of the subunit dimers. The resonance energy is determined as a function of the distance between the dimers of the (H2O)4 cluster. The temporary anion shape resonance of (NaCl)2 corresponds to an antibonding combination of the hybridized orbitals associated with the two Na atoms. The resonance energy is determined as a function of distortion along the totally symmetric normal coordinate.
Finally, the molecular virial theorem is studied for a H atom interacting with a uniform electric field or with a point charge. Analytical expressions of the contributions to changes in average kinetic and potential energies due to these interactions are obtained by use of Dalgarno-Lewis perturbation theory.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
16 September 2020 |
| Date Type: |
Publication |
| Defense Date: |
24 July 2020 |
| Approval Date: |
16 September 2020 |
| Submission Date: |
5 August 2020 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
113 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Non-valence anions, Non-valence anions |
| Date Deposited: |
16 Sep 2020 14:11 |
| Last Modified: |
16 Sep 2020 14:11 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/39656 |
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