A study of small molecules by molecular beam and laser techniques
A study of small molecules by molecular beam and laser techniques
The work presented in this thesis covers the technical development and related experiments of a molecular beam and laser apparatus for the study of reaction dynamics in well defined conditions via the formation of van der Waals complexes as precursors. It also includes Raman experiment performed on nitrosyl chloride (NOC1). Development of the visible laser induced fluorescence (LIF) has been carried out using molecular iodine in a jet and improving the spectrometer senstivity by monitoring fluorescence emission from the van der Waals complexes of iodine and the rare gas atoms. Experiments with argon revealed sets of peaks which were thought to originate from complexes formed only with iodine (dimers) because of the correlation found between the shifts of two consecutive sets of peaks and the shift of two consecutive uncomplexed iodine transitions. To confirm such an hypothesis, we carried out experiments with a neon-helium mixture. The results proved the efficiency of the apparatus to produce van der Waals complexes in the expansion together with a good sensitivity but failed to confirm our hypothesis since no set of peaks was observed. Ultra-violet LIF was carried out by studying the photodissociation of hydrogen peroxide at 248 nm and optimising radical detection. Our experimental results agree well with previous studies even though alignment parameters were not included. Another photodissociation experiment was peformed, on hypochlorous acid (HOC1) at 248nm. We found that most of the available energy is found in the OH radicals as translational energy. We also find a preference for the II3/2 spin-orbit state and for the II(A') lambda doublet state. Dissociation of HOC1 would take place in the plane of the molecule. The results on NOC1 at 266 showed overtones and combination bands of the O-C1 stretching vibration and the N-O-C1 bending vibration, which were not observed in our previous study. The dissociation at the wavelength would originate from the A state and therefore be very fast.
University of Southampton
1989
Pardon, Patrick Roger
(1989)
A study of small molecules by molecular beam and laser techniques.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The work presented in this thesis covers the technical development and related experiments of a molecular beam and laser apparatus for the study of reaction dynamics in well defined conditions via the formation of van der Waals complexes as precursors. It also includes Raman experiment performed on nitrosyl chloride (NOC1). Development of the visible laser induced fluorescence (LIF) has been carried out using molecular iodine in a jet and improving the spectrometer senstivity by monitoring fluorescence emission from the van der Waals complexes of iodine and the rare gas atoms. Experiments with argon revealed sets of peaks which were thought to originate from complexes formed only with iodine (dimers) because of the correlation found between the shifts of two consecutive sets of peaks and the shift of two consecutive uncomplexed iodine transitions. To confirm such an hypothesis, we carried out experiments with a neon-helium mixture. The results proved the efficiency of the apparatus to produce van der Waals complexes in the expansion together with a good sensitivity but failed to confirm our hypothesis since no set of peaks was observed. Ultra-violet LIF was carried out by studying the photodissociation of hydrogen peroxide at 248 nm and optimising radical detection. Our experimental results agree well with previous studies even though alignment parameters were not included. Another photodissociation experiment was peformed, on hypochlorous acid (HOC1) at 248nm. We found that most of the available energy is found in the OH radicals as translational energy. We also find a preference for the II3/2 spin-orbit state and for the II(A') lambda doublet state. Dissociation of HOC1 would take place in the plane of the molecule. The results on NOC1 at 266 showed overtones and combination bands of the O-C1 stretching vibration and the N-O-C1 bending vibration, which were not observed in our previous study. The dissociation at the wavelength would originate from the A state and therefore be very fast.
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Published date: 1989
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Local EPrints ID: 461931
URI: http://eprints.soton.ac.uk/id/eprint/461931
PURE UUID: 6a3d8a5e-8855-43fa-b137-e8211a996c2e
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Date deposited: 04 Jul 2022 18:58
Last modified: 04 Jul 2022 18:58
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Author:
Patrick Roger Pardon
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