UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Ultracold Atom-Atom Scattering with R-Matrix Methods

Rivlin, Tom; (2019) Ultracold Atom-Atom Scattering with R-Matrix Methods. Doctoral thesis (Ph.D), UCL (University College London). Green open access

[thumbnail of TomRivlinThesisPostVivaFinalDraft.pdf]
Preview
Text
TomRivlinThesisPostVivaFinalDraft.pdf - Accepted Version

Download (2MB) | Preview

Abstract

Novel experimental methods have allowed for the routine production of ultracold (sub-Kelvin) atoms and small molecules. This has facilitated the study of chemical reactions involving only a small number of partial waves, allowing for unprecedented control over ultracold chemical reactions. This thesis describes work towards a new set of theories, based on Wigner's R-matrix methodology, which are adapted for so-called heavy particle scattering, and in particular atom-atom scattering. From these new theories a new set of methods are constructed to accurately simulate scattering observables such as scattering lengths, cross-sections, and resonances for atom-atom scattering events at ultracold temperatures by producing high resolution plots of these observables. The methods utilise software built for high-accuracy diatomic spectra, such as Duo, to provide molecular eigenenergies and wavefunctions of the bound system at short internuclear distances (in a region known as the inner region), only requiring as input a matrix of diatomic internuclear potential energy curves and couplings. These methods then act as 'harnesses', allowing this information to be used to perform an R-matrix propagation at long internuclear distances (in a region known as the outer region) using R-matrix propagation codes such as PFARM. The result of this propagation is then used to produce the aforementioned scattering observables. In this work these new R-matrix methods are applied to the case of a particle scattering off a Morse potential, to elastic argon-argon collisions, and to the intramultiplet mixing of oxygen when impacted by helium. This work also serves as a basis for the future simulation of more complex scattering events, such as atom-diatom collisions and higher polyatomic collisions.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: Ultracold Atom-Atom Scattering with R-Matrix Methods
Event: UCL (University College London)
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
URI: https://discovery.ucl.ac.uk/id/eprint/10088428
Downloads since deposit
Loading...
242Downloads
Download activity - last month
Loading...
Download activity - last 12 months
Loading...
Downloads by country - last 12 months
1.United States
11
2.France
3
3.Russian Federation
3
4.Hong Kong
2
5.Philippines
1
6.Poland
1
7.United Kingdom
1
8.Oman
1
9.Singapore
1
10.Australia
1

Archive Staff Only

View Item View Item