<p> A detailed experimental and theoretical study has been performed on several different photochemical systems. Lead-salt tunable diode lasers operating in the infrared region have been used as diagnostic tools to probe the molecules in these gaseous systems. Knowledge of these systems is expected to be useful in evaluating future schemes of laser isotope separation.</p> <p> In the course of this work a computerized digital technique has been developed that allows molecular parameters such as linestrength and linewidth to be obtained by measuring the infrared absorption on vibrational-rotational transitions of the molecule. Molecular concentrations can then be determined enabling one to gain valuable insight into the chemical processes occurring in the system.</p> <p> The digital technique was first tested on CO2 gas in a multi-pass White cell to verify the validity of the measurements. Subsequently, measurements were performed on mixtures of NH3/N2, NH3/Ar, HTO/H2O, and HTO/air. Those NH3 measurements that could be compared to previous measurements were found to be very accurate. For the HTO system, no previous measurements on linestrength and linewidth for the transitions examined have been performed.</p> <p> Described next is the application of the tunable diode laser diagnostic system to the investigation of infrared multiphoton dissociation of deuterated chloroform immersed in a chloroform bath. The sensitivity of the technique allowed for the measurement of the few parts per million of DCl formed by the photolysis of natural abundance CDCl3 in CHCl3.</p><p> In addition, the feasibility of transient detection with tunable diode lasers was examined. High fluence CO2 laser pulses were used to dissociate C3F6 or C2F3Cl and create CF2 radicals. Current-modulation of the tunable diode laser made it possible to monitor the transient CF2 radicals as they were formed, and as they subsequently decayed. The sensitivity of the transient detection technique was found to be limited by detector noise.</p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19246 |
| Date | 09 1900 |
| Creators | Beckwith, Paul Henry |
| Contributors | Reid, J., Physics |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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