Physical Sciences and Mathematics Commons^™

Electronic Excitations In Branched Conjugated Oligomers: A Quasiparticle View And Tight-Binding Models, Hao Li

Wayne State University Dissertations

This dissertation focuses on the theoretical understanding and simulation of the excited state electronic structures of organic conjugated molecules. The exciton scattering (ES) approach has been extended for efficient calculation of optical spectra of large branched conjugated oligomers. The methodology of tight-binding (lattice) model, originally developed in condensed matter theory, has been extended to the building block structure of conjugated molecules for explicit description of the electronic excitations.

Within the ES approach, the electronic excitations in quasi-1D molecular structures are attributed to standing waves that represent quantum quasiparticles (excitons) scattered at the molecular vertices. Excitation energies can be found by …

Laser-Assisted Single-Molecule Refolding, Rui Zhao

Wayne State University Dissertations

Non-coding RNAs must fold into precise secondary and tertiary structures in order to perform the biological functions. Due to the flexibility of RNA, the RNA folding energy landscape can be rugged and full of local minimum (kinetic trap). To provide a means to study kinetically trapped RNAs, we have developed a new technique combining single-molecule FRET detection with laser induced temperature jump. We have calibrated the magnitude of the temperature jump with 1˚C accuracy using gold micro-size sensor. The accuracy of temperature calibration was confirmed by close agreement between single-molecule and bulk DNA duplex melting experiments.

HIV 1 DIS RNAs …

Astrochemical Dynamics: Fundamental Studies Relevant To Titan's Atmosphere, Wilson Kamundia Gichuhi

Wayne State University Dissertations

This work presents results of primary fundamental photodissociation and state-specific ion-molecule dynamical studies that are relevant to understanding the formation and growth mechanisms of unsaturated hydrocarbon molecules, haze layers and aerosols in Titan's upper atmosphere. In the diacetylene dimer, it is shown, via laboratory studies combined with electronic structure calculations that the photodissociation of the dimer readily initiates atomic hydrogen (H) loss and atomic H transfer reactions forming two prototypes of resonantly stabilized free radicals, C8H3 and C4H3, respectively. In ethylamine cation, high-level ab initio calculations identify the complex dissociation pathways for the ground state CH3CH2NH2+ radical cation at 233.3 …