Photodissociation Dynamics of Triatomic van der Waals Molecules
<p>The spectroscopy and vibrational predissociation dynamics of triatomic van der Waals molecules are studied experimentally and theoretically at the state-to-state level of detail. </p> <p>Laser-induced fluorescence spectra of HeCl<sub>2</sub> are measured and the g...
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| Format: | Others |
| Language: | en |
| Published: |
1988
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| Online Access: | https://thesis.library.caltech.edu/7412/1/Cline%20III_ji_1988.pdf Cline, Joseph Isaac, III (1988) Photodissociation Dynamics of Triatomic van der Waals Molecules. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/f38f-hb60. https://resolver.caltech.edu/CaltechTHESIS:01182013-155753371 <https://resolver.caltech.edu/CaltechTHESIS:01182013-155753371> |
| Summary: | <p>The spectroscopy and vibrational predissociation dynamics of triatomic van der Waals molecules are studied experimentally and theoretically at the state-to-state level of detail. </p>
<p>Laser-induced fluorescence spectra of HeCl<sub>2</sub> are measured and the geometry and vibrational predissociation rate are obtained by a rotational analysis of the spectra and the determination of homogenous linewidths. A laser pump-probe technique is used to measure the vibrational and rotational state population distribution of the product Cl<sub>2</sub>. Although the Cl<sub>2</sub> fragment has little rotational energy, its rotational distribution is bimodal. A symmetry selection rule for the dissociation results from the symmetry of the He • • • Cl<sub>2</sub> van der Waals potential. Quantum mechanical calculations on a realistic potential energy surface are successful in modeling the experimental spectroscopy and dynamics. </p>
<p>The vibrational predissociation dynamics of NeCl<sub>2</sub> is also measured using the pump-probe technique. In this case the Cl<sub>2</sub> fragment shows significantly more rotational excitation than in the dissociation of HeCl<sub>2</sub>. The rotational distributions are bimodal and are relatively independent of the energy of the prepared state. The NeCl<sub>2</sub> binding energy is estimated from thresholds for the populations of fragment rotational levels. </p>
<p>The vibrational predissociation of NeBr<sub>2</sub> is studied by dispersing the fluorescence of the Br<sub>2</sub> fragment. The product Br<sub>2</sub> is rotationally cold. The closure of vibrational product channels is used to determine the binding energy of the molecule. </p> |
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