Extending relativistic linear response theory to address solvent effects
(2022) Abstract
 The central aim of this thesis is to derive, implement and test new methods to calculate various types of spectroscopies of compounds containing heavy elements in an aqueous environment. Methods that can target such systems have to consider the following:
(i) It is crucial to take relativistic effects into account.
(ii) Modeling of larger systems is expensive in quantum chemistry. Thus, cheaper options need to be considered
for the water solvent.
(iii) Methods to calculate electronic spectra have to be able to model electronic excitations properly.
(i) The relativistic effects can be obtained by solving the Dirac equation. This yields a fourcomponent wave function, but methods based on only twocomponents have been... (More)  The central aim of this thesis is to derive, implement and test new methods to calculate various types of spectroscopies of compounds containing heavy elements in an aqueous environment. Methods that can target such systems have to consider the following:
(i) It is crucial to take relativistic effects into account.
(ii) Modeling of larger systems is expensive in quantum chemistry. Thus, cheaper options need to be considered
for the water solvent.
(iii) Methods to calculate electronic spectra have to be able to model electronic excitations properly.
(i) The relativistic effects can be obtained by solving the Dirac equation. This yields a fourcomponent wave function, but methods based on only twocomponents have been developed in this thesis. (ii) Larger systems can be tackled by dividing them into a region that is treated by methods from electronic structure theory, and a larger environment that is treated classically as a collection of localized static multipole moments (charges, dipole moments, etc.). In most such hybrid schemes (called QM/MM) we only take into account how the static multipole moments in the environment influence the wave function in the QM region. In this thesis, however, we allow mutual polarization of the regions through the polarizable embedding (PE) model. (iii) We calculate excited state properties through linear response theory. This has been developed to work with a variety of approximate state wave functions and has been extended to a relativistic framework. Moreover, it has been combined with PE. Yet, regular linear response theory suffers from problems in nonresonant regions of spectra. For this, we consider a variant of linear response theory, called the complex polarization propagator. Here, the lifetimes of the excited states are included in the response equations. This allows the calculation of spectra in regions that are problematic in regular response theory.
In this thesis, we have devised a method that combines relativistic CPP within a polarizable embedding framework. We employ the method on lightactivated platinum complexes with application in chemotheraphy. Here, both relativistic and solvent effects are crucial to model the excitation processes. Moreover, we also consider the calculation of electronic circular dichroism for chiral organic molecules that contain heavy elements like iodine. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3adae5cdefc44f088e42aae2f9cc2072
 author
 Creutzberg, Joel ^{LU}
 supervisor

 Erik Donovan Hedegård ^{LU}
 Ulf Ryde ^{LU}
 opponent

 Professor Christiansen, Ove, Aarhus University
 organization
 publishing date
 20221121
 type
 Thesis
 publication status
 published
 subject
 keywords
 Response theory, Polarizable embedding, Complex Polarization Propagator, Relativistic effects
 pages
 189 pages
 publisher
 Lunds Universitet/Lunds Tekniska Högskola
 defense location
 Kemicentrum, sal A (KC:A), Lund University
 defense date
 20221215 13:00:00
 ISBN
 9789174229233
 9789174229226
 language
 English
 LU publication?
 yes
 id
 3adae5cdefc44f088e42aae2f9cc2072
 date added to LUP
 20221121 16:26:04
 date last changed
 20221124 10:07:42
@phdthesis{3adae5cdefc44f088e42aae2f9cc2072, abstract = {{The central aim of this thesis is to derive, implement and test new methods to calculate various types of spectroscopies of compounds containing heavy elements in an aqueous environment. Methods that can target such systems have to consider the following:<br/>(i) It is crucial to take relativistic effects into account.<br/>(ii) Modeling of larger systems is expensive in quantum chemistry. Thus, cheaper options need to be considered<br/>for the water solvent.<br/>(iii) Methods to calculate electronic spectra have to be able to model electronic excitations properly.<br/>(i) The relativistic effects can be obtained by solving the Dirac equation. This yields a fourcomponent wave function, but methods based on only twocomponents have been developed in this thesis. (ii) Larger systems can be tackled by dividing them into a region that is treated by methods from electronic structure theory, and a larger environment that is treated classically as a collection of localized static multipole moments (charges, dipole moments, etc.). In most such hybrid schemes (called QM/MM) we only take into account how the static multipole moments in the environment influence the wave function in the QM region. In this thesis, however, we allow mutual polarization of the regions through the polarizable embedding (PE) model. (iii) We calculate excited state properties through linear response theory. This has been developed to work with a variety of approximate state wave functions and has been extended to a relativistic framework. Moreover, it has been combined with PE. Yet, regular linear response theory suffers from problems in nonresonant regions of spectra. For this, we consider a variant of linear response theory, called the complex polarization propagator. Here, the lifetimes of the excited states are included in the response equations. This allows the calculation of spectra in regions that are problematic in regular response theory. <br/>In this thesis, we have devised a method that combines relativistic CPP within a polarizable embedding framework. We employ the method on lightactivated platinum complexes with application in chemotheraphy. Here, both relativistic and solvent effects are crucial to model the excitation processes. Moreover, we also consider the calculation of electronic circular dichroism for chiral organic molecules that contain heavy elements like iodine.}}, author = {{Creutzberg, Joel}}, isbn = {{9789174229233}}, keywords = {{Response theory; Polarizable embedding; Complex Polarization Propagator; Relativistic effects}}, language = {{eng}}, month = {{11}}, publisher = {{Lunds Universitet/Lunds Tekniska Högskola}}, school = {{Lund University}}, title = {{Extending relativistic linear response theory to address solvent effects}}, url = {{https://lup.lub.lu.se/search/files/129101154/thesis_Joel_Creutzberg_WEBB.pdf}}, year = {{2022}}, }