dc.contributor.author
Schröder, Maike
dc.date.accessioned
2018-06-08T01:14:51Z
dc.date.available
2005-02-17T00:00:00.649Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/13134
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-17332
dc.description
Titelblatt und Inhaltsverzeichnis
Gutachter
1 Introduction
11
1.1 Overview
11
1.2 Cage Effect
14
1.3 Chromophore Dynamics
17
1.4 Lattice Dynamics
21
1.4.1 Shock Waves
21
1.4.2 Excitation of Coherent Phonons
24
1.5 Spectroscopy of Chromophore-Matrix Interaction
26
1.5.1 Pump-Probe Spectroscopy
27
1.5.1.1 Vibrational Relaxation
31
1.5.2 Example: I2 in Kr
33
2 Dynamics Simulation of Many-Body Systems
37
2.1 Classical Molecular Dynamics
37
2.2 Quantum-Classical Dynamics
38
2.2.1 Mean-Field Approach
39
2.2.2 Classical Separable Potential Method
39
2.3 Surface Hopping
40
3 Model Systems
43
4 Diatomics in Molecules - DIM
53
4.1 Potentials for XY in Argon
53
4.2 Wavefunctions
54
4.2.1 Construction of the VB-Wavefunctions
55
4.2.2 Example
58
4.3 Interaction with Argon
60
4.4 Spin-Orbit Coupling
62
4.4.1 Representation of Spin-Orbit Coupling in the Basis of the Model
Hamiltonian
67
4.4.1.1 Application to the Molecular VB-Wavefunctions
75
4.4.1.2 Example
76
4.4.2 Electron-Hole Dualism
79
5 Simulation Methods
81
5.1 Classical Dynamics
82
5.2 Finite Differences Method
83
5.3 Tabulation of the Potential
84
5.4 Periodic Boundary Conditions
86
5.5 State Transitions
88
6 Cl2 in Ar
91
6.1 DIM-Potentials and Interactions
91
6.2 Ground State Geometry
92
6.3 Potentials for Cl2 in Ar
94
6.3.1 Matrix Shift
96
6.4 Assignment of Electronic States
96
6.5 2D-Potential Surfaces
99
6.6 C-State Excitation
101
6.6.1 Energy Distribution in the Lattice
104
6.6.1.1 Shock Wave
104
6.6.1.2 Energy Distribution in Different Layers
107
6.7 B-State Excitation
110
6.7.1 Energy Distribution with Different Initial Energies
112
6.7.1.1 Excitation Above the Dissociation Limit
114
6.7.1.2 Excitation Below Dissociation Limit
118
6.7.1.3 Excitation Near the Potential Minimum
121
6.7.1.4 The Role of the Wavefunction
123
6.7.1.5 Lattice Vibrations
125
6.7.1.6 Vibrational Relaxation
128
6.8 Discussion
130
7 ClF in Ar
133
7.1 DIM-Potentials and Interactions
133
7.2 Geometry
134
7.3 Potentials
136
7.3.1 Matrix Shift
137
7.4 2D-Potentials Surfaces
137
7.5 Dynamics of ClF in Ar
140
7.5.1 Excitation to the 1Π State
141
7.6 Spin-Flip
143
7.7 Discussion
146
8 Summary
153
8.1 Cl2 in Ar
153
8.2 ClF in Ar
155
Bibliography
157
Danksagung
dc.description.abstract
In this thesis the photodissociation dynamics of diatomic molecules embedded
in a rare gas environment was investigated. The objective was a mechanistic
understanding of molecular dynamics in condensed matter with respect to guest-
host interactions and state transitions to explain specific features relevant
for pump-probe spectroscopy.
Therefore, two model systems were chosen, the symmetric Cl2 and the asymmetric
ClF molecule, embedded in an argon matrix. Both systems reveal interesting
features, e.g. distinctive photodissociation dynamics and guest-host
interactions are to be expected, as the different orientations of these
molecules in the host lattice lead to different mechanisms of caging.
The potentials and interactions of the systems were calculated using the
Diatomics in Molecules method. This approach accounts for the different
electronic states of the molecule as well as the pair-interactions between the
chromophore fragments and the rare gas atoms. Also spin-orbit interaction was
included, which leads to a coupling between the adiabatic states. The dynamics
was described by classical trajectory simulations. Additionally, the
significance of nonadiabatic transitions was estimated to gain insight into
the intersystem crossing observed for both systems.
de
dc.description.abstract
In dieser Arbeit wurde die Photodissoziation zweiatomiger Moleküle in einer
Edelgasumgebung theoretisch untersucht. Ziel war es, einen detaillierteren
Einblick in die Mechanismen der Moleküldynamik in kondensierter Phase zu
erhalten. Von besonderem Interesse füur das qualitative Verständnis
spezifischer Charakteristika von Pump-Probe Spektren sind dabei Chromophor-
Gitter Wechselwirkungen und matrixinduzierte nicht-adiabatische Übergäange.
Als Modellsysteme wurden das symmetrische Cl2 und das asymmetrische ClF in
einer Argonmatrix betrachtet. Beide Systeme zeigen interessante Eigenschaften.
Aufgrund unterschiedlicher Orientierungen dieser Moleküle in der Edelgasmatrix
können in Folge unterschiedlicher Wechselwirkungen verschiedene Abläufe der
Molekulardynamik erwartet werden.
Die Potentiale und Wechselwirkungen der Systeme wurden in Rahmen der Diatomics
in Molecules Methode berechnet. Dieser Ansatz berücksichtigt neben
verschiedenen elektronischen Zuständen des Moleküls auch sämtliche atomare
Paar-Wechselwirkungen innerhalb des Systems. Des weiteren wurden Spin-Bahn
Wechselwirkungen einbezogen, die zu einer Kopplung zwischen den adiabatischen
Zuständen führen. Die Dynamik wurde durch klassische Trajektorien beschrieben.
Zur Aufklärung des in beiden Systemen beobachteten Intersystem-Crossings wurde
die Bedeutung nicht-adiabatischer Übergänge abgeschätzt.
de
dc.rights.uri
http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen
dc.subject
condensed phase
dc.subject
photodissociation dynamics
dc.subject.ddc
500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften
dc.title
Theoretical Investigation of the Ultrafast Photodissociation Dynamics of
Diatomic Molecules in a Rare Gas Environment
dc.contributor.firstReferee
Priv. Doz. Dr. Oliver Kühn
dc.contributor.furtherReferee
Prof. Dr. R.B. Gerber
dc.date.accepted
2004-09-06
dc.date.embargoEnd
2005-02-18
dc.identifier.urn
urn:nbn:de:kobv:188-2005000436
dc.title.translated
Theoretische Untersuchungen zur Ultrakurzzeitdynamik zweiatomiger Moleküle in
Edelgasumgebung
de
refubium.affiliation
Biologie, Chemie, Pharmazie
de
refubium.mycore.fudocsId
FUDISS_thesis_000000001882
refubium.mycore.transfer
http://www.diss.fu-berlin.de/2005/43/
refubium.mycore.derivateId
FUDISS_derivate_000000001882
dcterms.accessRights.dnb
free
dcterms.accessRights.openaire
open access