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Electronic Structure and Dynamics for Molecules Near Metal Surfaces
Electronic Structure and Dynamics for Molecules Near Metal Surfaces
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211151314
- ISBN
- 9798382835419
- DDC
- 540
- 저자명
- Chen, Junhan.
- 서명/저자
- Electronic Structure and Dynamics for Molecules Near Metal Surfaces
- 발행사항
- [Sl] : University of Pennsylvania, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 178 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 85-12, Section: B.
- 주기사항
- Advisor: Subotnik, Joseph E.
- 학위논문주기
- Thesis (Ph.D.)--University of Pennsylvania, 2024.
- 초록/해제
- 요약Molecular dynamics at metal interfaces is a critical research area that underlies significant chemical processes involved in technology, energy and medical applications. The Born-Oppenheimer approximation, which is the fundamental theoretical approximation underlying almost all ab initio molecular dynamics approaches, often breaks down at interfaces, because charge transfer occurs and nuclei move along multiple potential energy surfaces. The presence of such complicated curve crossings requires that a meaningful theoretical description must involve not just one unique ground state, but also one or more relevant excited states. Obtaining such states becomes extremely hard near metal surfaces, as hard as picking a needle in a haystack, because there is a continuum of electronic states present at metal surfaces: how should we pick the relevant electronic states (assuming many states are irrelevant)? In this thesis, we develop several electronic structure methods for solving such a problem, using the Anderson impurity model as a test case. On the one hand, to test our methodologies, we quantitatively benchmark our results for ground state properties against numerical exact results from numerical renormalization group (NRG) theory. On the other hand, to learn about new physical processes, we qualitatively assess the predicted excited state properties, especially curve crossing trends. As far as methods are concerned, we first investigate a selective configuration interaction approach; here, ground state results match with NRG results across a wide range of parameters, but we find this approach is not easy to extrapolate to realistic systems. Second, we investigate a multireference Hartree-Fock wave function, with both open-shell and closed-shell characters; here, again, we find strong ground state results and show that effectively an active space can be isolated, but we find that the algorithm in some ways does not include enough electronic relaxation. Third, we design a new complete active space approach based on a novel constraint appropriate to interfaces. This last approach appears to be the very best of all choices so far and can generate both accurate ground state wave function as well as excited states, all with smooth transitions. Using the latter approach, future development of gradients and non-adiabatic couplings should allow for the study of non-adiabatic dynamics for molecules near metal surfaces.
- 일반주제명
- Chemistry
- 일반주제명
- Physical chemistry
- 일반주제명
- Computational chemistry
- 일반주제명
- Molecular chemistry
- 기타저자
- University of Pennsylvania Chemistry
- 기본자료저록
- Dissertations Abstracts International. 85-12B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520250211151314
■006m o d
■007cr#unu||||||||
■020 ▼a9798382835419
■035 ▼a(MiAaPQ)AAI31238125
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a540
■1001 ▼aChen, Junhan.
■24510▼aElectronic Structure and Dynamics for Molecules Near Metal Surfaces
■260 ▼a[Sl]▼bUniversity of Pennsylvania▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a178 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 85-12, Section: B.
■500 ▼aAdvisor: Subotnik, Joseph E.
■5021 ▼aThesis (Ph.D.)--University of Pennsylvania, 2024.
■520 ▼aMolecular dynamics at metal interfaces is a critical research area that underlies significant chemical processes involved in technology, energy and medical applications. The Born-Oppenheimer approximation, which is the fundamental theoretical approximation underlying almost all ab initio molecular dynamics approaches, often breaks down at interfaces, because charge transfer occurs and nuclei move along multiple potential energy surfaces. The presence of such complicated curve crossings requires that a meaningful theoretical description must involve not just one unique ground state, but also one or more relevant excited states. Obtaining such states becomes extremely hard near metal surfaces, as hard as picking a needle in a haystack, because there is a continuum of electronic states present at metal surfaces: how should we pick the relevant electronic states (assuming many states are irrelevant)? In this thesis, we develop several electronic structure methods for solving such a problem, using the Anderson impurity model as a test case. On the one hand, to test our methodologies, we quantitatively benchmark our results for ground state properties against numerical exact results from numerical renormalization group (NRG) theory. On the other hand, to learn about new physical processes, we qualitatively assess the predicted excited state properties, especially curve crossing trends. As far as methods are concerned, we first investigate a selective configuration interaction approach; here, ground state results match with NRG results across a wide range of parameters, but we find this approach is not easy to extrapolate to realistic systems. Second, we investigate a multireference Hartree-Fock wave function, with both open-shell and closed-shell characters; here, again, we find strong ground state results and show that effectively an active space can be isolated, but we find that the algorithm in some ways does not include enough electronic relaxation. Third, we design a new complete active space approach based on a novel constraint appropriate to interfaces. This last approach appears to be the very best of all choices so far and can generate both accurate ground state wave function as well as excited states, all with smooth transitions. Using the latter approach, future development of gradients and non-adiabatic couplings should allow for the study of non-adiabatic dynamics for molecules near metal surfaces.
■590 ▼aSchool code: 0175.
■650 4▼aChemistry
■650 4▼aPhysical chemistry
■650 4▼aComputational chemistry
■650 4▼aMolecular chemistry
■653 ▼aMolecular dynamics
■653 ▼aAnderson impurity model
■653 ▼aNumerical renormalization group theory
■653 ▼aBorn-Oppenheimer approximation
■653 ▼aHartree-Fock wave function
■690 ▼a0485
■690 ▼a0494
■690 ▼a0219
■690 ▼a0431
■71020▼aUniversity of Pennsylvania▼bChemistry.
■7730 ▼tDissertations Abstracts International▼g85-12B.
■790 ▼a0175
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17161133▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
