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Item Infrared induced dynamics of loosely bound molecules : the dynamical process of vibrational state to continuum coupling for trans-1, 2-dichloroethylene (DCE) using infrared spectroscopy : Master of Science in Physics at Massey University, Albany, New Zealand(Massey University, 2019) Alrsheedi, Fatimah N.The infrared absorption spectrum of crystalline trans-1, 2-dichloroethylene has been measured down to 50 K using a specially designed and constructed infrared (IR) cell, using a Nicolet iS50R FT-IR. The IR scans show the absorbance of trans-1, 2-dichloroethylene molecules at bu CH stretch (9), bu CH bend (10), au CH bend (6) and bu CCl stretch (11) are changed at different temperature conditions. In the solid phase, the absorption spectra of crystalline trans -1, 2-dichloroethylene at different temperatures demonstrates a dramatic change in some of the peak shapes for bu CH stretch (9), bu CH bend (10), au CH bend (6) and bu CCl stretch (11). Instead of a symmetric lineshape that would generally be expected for the excitations of these modes, the spectra clearly showed asymmetric lineshape in some of the peaks as result of the presence of Fano resonance which is not commonly seen in infrared spectroscopy. Although asymmetric peaks are often attributed to interference from reflected rays due to refractive index changes at boundary surfaces the observation, in some cases, of complete peak inversion allows for an unambiguous identification of Fano interference as the source of the asymmetry. The origin of this effect refers to quantum interference on the optical absorption through the coupling between the discrete and continuum states in which the excited eigenstates are mixtures of the discrete and continuum states, as the excitation of trans -1, 2-dichloroethylene occurring simultaneously with the continuum background transitions. In this thesis, we report IR spectroscopic observations that show interference between the vibrational states of the molecules of trans -1, 2- dichloroethylene with the continuum background states. The background continuum arises from the overlapping of many other resonances due to the overtone/ combination bands and coupling of other vibrational states, including the bulk optical phonons, providing essentially a broad continuum. Individual resonances are conspicuous at low temperature and continuously reduce with increasing temperature. Additionally, the IR bands for the fundamental modes have been observed and discussed in this work. Further, the overtone and combination bands are also assigned on the basis of (gas phase) anharmonic calculations as the analysis of anharmonic and harmonic frequencies shows that the anharmonic frequencies are close and correspond better with the experiment than those acquired using a harmonic approximation.Item Investigation into the interactions of supercritical argon as a solvent with trans-1,2-dichloroethylene using ultraviolet-visible and infrared spectroscopy : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Chemistry at Massey University, Auckland, New Zealand(Massey University, 2018) Moffet, Erin SarahThis thesis looks at the uses and interactions of argon as a solvent at or above its supercritical temperature and pressure. A supercritical fluid allows for a range of properties depending on where the conditions of pressure and temperature are in relation to the critical point of the chosen substance. These supercritical fluids have been shown to be useful across many areas of industry and research and are the ideal fluid to use in a molecular beam pulsed valve. Solubility interactions of argon and trans-1,2-dichloroethylene (DCE) across multiple conditions were monitored using ultraviolet-visible (UV-Vis) and infrared (IR) spectroscopy. Two high pressure cells were designed, constructed and tested to withstand the 50 atmospheres and 140 K conditions required. The initial cell focused on UV-Vis spectroscopy with the DCE vapour showing an exponential decrease in absorbance as the temperature in the cell was reduced. Changing conditions to reach the supercritical region of argon resulted in a significant increase in the absorbance and therefore the solubility of DCE. The second cell constructed focuses on analysis using infrared spectroscopy and showed clear peak shifts and shape changes at the bu CH stretch (ν9) and bu CH bend (ν10) for trans-1,2-dichloroethylene (DCE) The intensity at au CH bend (ν6) and bu CCl stretch (ν11) proved to be less informative. DCE vapour acted predictably as the temperature was reduced, resulting in a significant drop off in absorbance similar to that observed in the UV-Vis. In changing to the supercritical and liquid argon conditions resulted in the appearance of an asymmetric lineshape characteristic of Fano resonance, which is not common in infrared spectroscopy. This suggest that there is an interaction occurring between a discrete state of DCE that couples to a background continuum process. This Fano resonance does not appear to be present in an argon matrix isolation.Item SEIRAS of functionalised graphene nanomaterials : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nanoscience at Massey University, Manawatū, New Zealand(Massey University, 2017) Fisher, EwanGraphene exhibits many excellent properties, but many next-generation devices require post chemical treatment to introduce structural confirmations, defects or a particular impurity to obtain functionality. The understanding of these defects and the manifestation of desirable properties using chemical modification is a fundamental problem with low defect graphene as the small number of functional groups provides insufficient signal intensity for many characterisation techniques. Metallic nanoparticles are at the centre of plasmonics for enhancing optical signals. This work is a unique undertaking for the examination of novel Steglich esterification chemistry that is performable on graphene as well as providing insight into the native edge structure of as-produced graphene flakes using surface enhanced infrared reflection absorption spectroscopy (SEIRAS) to characterise covalently functionalised graphene materials. Two methods of producing graphene flakes that are relatively low or high in defects have been developed to contrast the effect that inherent defects have on the macroscopic physical and spectroscopic properties. Ultraviolet-visible spectroscopy in conjunction with Raman, electron and atomic force microscopy was used to elucidate the origins and density of defects to draw conclusions on how graphene’s macroscopic properties manifest from atomic level defects. Discussions of infrared vibrational spectroscopy are carried out before an extension to SEIRAS where the use of near-field plasmon and phonon modes are attributed to observed optical enhancements. The experimental preparation is focused towards understanding the role nanoparticles play in SEIRAS of graphene and is discussed such that other graphene researchers can recreate SEIRAS for their graphene research. TEM is used to characterise the variety of nanoparticle shapes and geometries as well as provide topological insights on nanoparticles adsorbed to flakes of graphene. SEIRAS probes the defects native to graphene which confirms the presence of oxygen functionality. Steglich esterification reactions were utilised to successfully prepare a range of graphene materials with novel covalently bound functional groups as confirmed by SEIRAS. Covalent chemistry was extended to introduce a redox-active ferrocene derivative where SEIRAS was used to observe in real-time, the effect of interconversion of ferrocene to the ferrocenium cation. The foundations for the development of graphene-based solid state solar cells was the final focus of this work. Development and production of a potential photo-active layer was explored with Cl-BODIPY as the basis chromophore. Production of a flexible, electrically conductive substrate from graphene flakes was carried out, and tunnelling electron microscopy (TEM) was used to characterise topological and morphological surface features. The focus here was on covalent and physical absorption to graphene flakes. SEIRAS was used to confirm nucleophilic substitution (covalent) modification while STEM was used to confirm the uniformity of BODIPY on the substrate and chlorine atomic mapping to confirm physisorption.