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  • 2021PeterFletcherPhD

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Development of Density Functional Methods for Electronic Excited States and the Influence of Molecular Structure on Electronic Excited States

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@phdthesis{77f75fb36e3e47d5ba5506ad380faae9,
title = "Development of Density Functional Methods for Electronic Excited States and the Influence of Molecular Structure on Electronic Excited States",
abstract = "An extensive assessment of six density functional approximations has beenundertaken, each of these approximations have their own merits and faults.Range separated hybrids are the best performing for excited state propertiesof those approximations assessed.There has been an attempt to generate an attenuated form of PBE(CAM-PBE) which initially had issues which were investigated in detailregarding the dependence of Hartree–Fock exchange energy on approximation performance. This attenuated form of PBE had similar performance toCAM-B3LYP.The development of a set of benchmark data for excited state geometriesand emission energies was undertaken with a wide range of organic moleculesdue to the lack of such benchmark data existing currently. This meansthe accuracy of density functional approximations for calculation of suchproperties is unknown so there is a clear need for this benchmark data tobe developed and used to assess the accuracy of these approximations.The benchmark data for excited state geometries and emission energieswas used to assess the performance of a range of density functional approximations for these properties. This assessment has suggested that there are issues when applying current density functional approximations away fromthe ground state where they have been tuned and optimised. This suggeststhat there may be some merit in developing specialised density functionalapproximations for the calculation of excited state properties.The existing density functional approximations have been used to assist with experimental investigations of porous polymers and in explainingthe excited state properties of these polymers. This was done using modelsystems and has enabled a deeper understanding of the experimental observations",
keywords = "Density function theory (DFT), DENSITY FUNCTIONALS, TDDFT, ELECTRONIC EXCITATIONS, Electronic excited states, POROUS MATERIALS, Benchmarking, Benchmark datasets, MOLECULAR STRUCTURE, Electronic structure, Quantum chemistry, Quantum chemical calculations, Theoretical chemistry",
author = "Peter Fletcher",
year = "2021",
doi = "10.17635/lancaster/thesis/1388",
language = "English",
publisher = "Lancaster University",
school = "Lancaster University",

}

RIS

TY - THES

T1 - Development of Density Functional Methods for Electronic Excited States and the Influence of Molecular Structure on Electronic Excited States

AU - Fletcher, Peter

PY - 2021

Y1 - 2021

N2 - An extensive assessment of six density functional approximations has beenundertaken, each of these approximations have their own merits and faults.Range separated hybrids are the best performing for excited state propertiesof those approximations assessed.There has been an attempt to generate an attenuated form of PBE(CAM-PBE) which initially had issues which were investigated in detailregarding the dependence of Hartree–Fock exchange energy on approximation performance. This attenuated form of PBE had similar performance toCAM-B3LYP.The development of a set of benchmark data for excited state geometriesand emission energies was undertaken with a wide range of organic moleculesdue to the lack of such benchmark data existing currently. This meansthe accuracy of density functional approximations for calculation of suchproperties is unknown so there is a clear need for this benchmark data tobe developed and used to assess the accuracy of these approximations.The benchmark data for excited state geometries and emission energieswas used to assess the performance of a range of density functional approximations for these properties. This assessment has suggested that there are issues when applying current density functional approximations away fromthe ground state where they have been tuned and optimised. This suggeststhat there may be some merit in developing specialised density functionalapproximations for the calculation of excited state properties.The existing density functional approximations have been used to assist with experimental investigations of porous polymers and in explainingthe excited state properties of these polymers. This was done using modelsystems and has enabled a deeper understanding of the experimental observations

AB - An extensive assessment of six density functional approximations has beenundertaken, each of these approximations have their own merits and faults.Range separated hybrids are the best performing for excited state propertiesof those approximations assessed.There has been an attempt to generate an attenuated form of PBE(CAM-PBE) which initially had issues which were investigated in detailregarding the dependence of Hartree–Fock exchange energy on approximation performance. This attenuated form of PBE had similar performance toCAM-B3LYP.The development of a set of benchmark data for excited state geometriesand emission energies was undertaken with a wide range of organic moleculesdue to the lack of such benchmark data existing currently. This meansthe accuracy of density functional approximations for calculation of suchproperties is unknown so there is a clear need for this benchmark data tobe developed and used to assess the accuracy of these approximations.The benchmark data for excited state geometries and emission energieswas used to assess the performance of a range of density functional approximations for these properties. This assessment has suggested that there are issues when applying current density functional approximations away fromthe ground state where they have been tuned and optimised. This suggeststhat there may be some merit in developing specialised density functionalapproximations for the calculation of excited state properties.The existing density functional approximations have been used to assist with experimental investigations of porous polymers and in explainingthe excited state properties of these polymers. This was done using modelsystems and has enabled a deeper understanding of the experimental observations

KW - Density function theory (DFT)

KW - DENSITY FUNCTIONALS

KW - TDDFT

KW - ELECTRONIC EXCITATIONS

KW - Electronic excited states

KW - POROUS MATERIALS

KW - Benchmarking

KW - Benchmark datasets

KW - MOLECULAR STRUCTURE

KW - Electronic structure

KW - Quantum chemistry

KW - Quantum chemical calculations

KW - Theoretical chemistry

U2 - 10.17635/lancaster/thesis/1388

DO - 10.17635/lancaster/thesis/1388

M3 - Doctoral Thesis

PB - Lancaster University

ER -