Laser predissociation spectroscopy of supersonic molecular beams /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1988.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | Two laser spectroscopic studies of predissociation in a supersonic molecular beam are discussed in this thesis. In the first of these experiments, the optothermal infrared predissociation spectrum of the weakly bound molecular complex OC-HF is obtained. The rotational structure of the v1 fundamental and hot band v1 + v(1/5) - v(1/5) is analyzed along with transitions observed in the gas phase spectrum of the complex to provide values for band origins and rotational and distortion constants of the initial (0000[^0]0, 0000[^0]1[^1]) and excited (1000[^0]0[^0], 1000[^0]1[^1]) states. From the l-type doubling constant for the 0000[^0]1[^1] state, the frequency of the v5 vibration is estimated. To vibrational analysis of v1 + v(1/5) - v(1/5) also allows the overtone hot band v1 + 2v(2/5) 2v(2/5), observed in the gas phase, to be assigned and molecular constants for the 0000[^0]2[^2] and 1000[^0]2[^2] states to be determined. The gas phase spectrum of the v1 + v3 - v3 band is analyzed, and evidence of perturbation in this band and the v5 hot bands is explained by the small energy spacing between v3 and v5. From these analyses of the fundaments and hot bands, the potential energy hypersurface of the complex is characterized by the anharmonicity constants x15 and x13, and the rotation-vibration interaction constants a1, a3, and a5. In addition, linewidths observed in the supersonic beam spectra permit precise determination of predissociative lifetimes in the 1000[^0]0[^0] state. The purpose of the second study is to demonstrate the use of condenser microphone as a detector in laser predissociation spectroscopy of supersonic molecular beams. As a test case, predissociation from the B3Π[+ou] state of I2[127] is observed. Partially resolved structure in individual rotational lines is attributed to nuclear electric quadrupole and magnetic spin rotation interactions. Simulated spectra are derived from a calculation of hyperfine structure and an analysis of rates of various laser-induced processes occurring in the supersonic beam, and are shown to agree well with the observed spectral profiles. The sensitivity of the microphone under experimental conditions is calculated, and, expressed as the minimum detectable flow rate, is found to be 9.7 x 10^9 molecules s^-1. Approaches to designing an experiment which fully realizes the capabilities of microphone detection are discussed. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Chemistry." |
| Physical Description: | x, 84 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |