New insights into the kinetic and molecular dynamics of liquids are presented through two distinct experimental studies. The kinetics and dynamics of cold 12 molecules scattered off liquid polydimethylsiloxane are studied. Time resolved LIF spectra give number densities and quantum state populations throughout both the inelastic scattering and the trapping/ desorption processes. The vibrational cooling of inelastically scattered molecules indicates different mechanisms for the trapping and desorption processes. Surface temperature dependence yields desorption enthalpy 23 - 30 kJ moZ-1 and frequency factor 108 - 1010 Hz, thus suggesting predesorption diffusion. Dynamical behaviour indicates more than one mechanism for activation of trapped species, i.e., conversion of internal energy into translation and energising via interaction with liquid molecules. The molecular dynamics of vertical liquid jets produced by slit nozzles was determined. The alignment of rhodamine 6G molecules, seeded in ethylene glycol jets, is evaluated through polarised laser induced fluorescence (PLF). Computational fitting and integration produce the corresponding liquid velocity distributions. Different streams within the jets are identified. The study is extended to the alignment inside the nozzle. An asymmetric nozzle flow is studied in order to verify the conclusions drawn. An interpretation of the lobed jet kinetics and molecular dynamics is proposed by relating the velocity distributions with the jet horizontal sections.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:332794 |
| Date | January 1993 |
| Creators | Quintella, Cristina M. A. L. T. Mata H. |
| Publisher | University of Sussex |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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