Sökning: "Ground and Excited States"

Visar resultat 1 - 5 av 79 avhandlingar innehållade orden Ground and Excited States.

1. 1. Ground and Excited State Aromaticity : Design Tools for π-Conjugated Functional Molecules and Materials

   Författare :Christian Dahlstrand; Henrik Ottosson; Miguel Solà; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fulvene; fulvalene; polyfulvene; aromaticity; triplet state; excited state; Clar structure; polybenzenoid hydrocarbons PBH ; conjugated polymers; computational chemistry; optical spectroscopy; Kemi med inriktning mot organisk kemi; Chemistry with specialization in Organic Chemistry;

   Sammanfattning : The main focus of this thesis is on the aromaticity of the ground state and electronically excited states of π-conjugated molecules and polymers, as well as how aromaticity is connected to their properties.The electronic structures of polybenzenoid hydrocarbons (PBHs) were explored through density functional theory (DFT) calculations and the π-component of the electron localization function (ELFπ). LÄS MER

3. 2. Excited State Aromaticity and Antiaromaticity : Fundamental Studies and Applications

   Författare :Rabia Ayub; Henrik Ottosson; Manabu Abe; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Baird s rule; Clar s rule; Computational quantum chemistry; Excited state aromaticity; Excited state aromaticity indicators; Organic photochemistry; Polycyclic conjugated hydrocarbons; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Sammanfattning : The central theme of this thesis is the ability to tune various molecular properties by controlling and utilizing aromaticity and antiaromaticity in the lowest electronically excited states. This investigation is based on qualitative theory, quantum chemical (QC) calculations and experimental work. LÄS MER

4. 3. Ultrafast Dynamics in Ground and Excited States of Porphyrin Molecules

   Författare :Peter Martinsson; Kemisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; intra- and intermolecular dynamics.; Zn-porphyrin; bacteriochlorophyll a; chlorophyll b; Femtosecond transient absorption spectroscopy; chlorophyll a; Physical chemistry; Fysikalisk kemi;

   Sammanfattning : This thesis describes inter and intramolecular dynamics in porphyrin molecules. To create a basis for understanding the energy and electron transfer processes in photosynthesis, the ultrafast dynamics of monomeric chlorophyll a, chlorophyll b and bacteriochlorophyll a were studied with ultrashort laser pulses. LÄS MER

5. 4. Theoretical Studies of Ground and Excited State Reactivity

   Författare :Pooria Farahani; Marcus Lundberg; Hans Karlsson; Isabelle Navizet; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical Reactivity; Computational Chemistry; Dynamics; Ground and Excited States; Chemiluminescence; Atmospheric Chemistry;

   Sammanfattning : To exemplify how theoretical chemistry can be applied to understand ground and excited state reactivity, four different chemical reactions have been modeled. The ground state chemical reactions are the simplest models in chemistry. To begin, a route to break down halomethanes through reactions with ground state cyano radical has been selected. LÄS MER

7. 5. Negative ion experiments at DESIREE : Photodetatchment studies of transitions and lifetimes of excited states of Ir-

   Författare :Moa Kristiansson; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fysik; Physics;

   Sammanfattning : In this thesis I present measurements using laser photodetachment to investigate negative ions of iridium produced in a cesium sputter ion source and stored in the cryogenic storage ring, DESIREE. The ions are photodetached by either a tunable OPO laser system or a tunable narrow bandwidth Titanium Sapphire laser. LÄS MER