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Please use this identifier to cite or link to this item: http://hdl.handle.net/10204/4361

Title: Comparative study of the dissociative ionization of 1,1,1-trichloroethane using nanosecond and femtosecond laser pulses
Authors: Du Plessis, A
Strydom, C
Botha, L
Keywords: Laser ionization
Laser dissociation
Coherent control
Ttrichloroethane
Molecular science
Nanosecond laser pulses
Femtosecond laser pulses
Issue Date: Mar-2010
Publisher: MDPI
Citation: Du Plessis, A, Strydom, C and Botha, L. 2010. Comparative study of the dissociative ionization of 1,1,1-trichloroethane using nanosecond and femtosecond laser pulses. International Journal of Molecular Science, Vol. 11(3), pp 1114-1140
Abstract: Changes in the laser induced molecular dissociation of 1,1,1-trichloroethane (TCE) were studied using a range of intensities and standard laser wavelengths with nanosecond and femtosecond pulse durations. TCE contains C-H, C-C and C-Cl bonds and selective bond breakage of one or more of these bonds is of scientific interest. Using laser ionization time of flight mass spectrometry, it was found that considerable variation of fragment ion peak heights as well as changes in relative peak ratios is possible by varying the laser intensity (by attenuation), wavelength and pulse duration using standard laser sources. The nanosecond laser dissociation seems to occur via C-Cl bond breakage, with significant fragmentation and only a few large mass ion peaks observed. In contrast, femtosecond laser dissociative ionization results in many large mass ion peaks. Evidence is found for various competing dissociation and ionization pathways. Variation of the nanosecond laser intensity does not change the fragmentation pattern, while at high femtosecond intensities large changes are observed in relative ion peak sizes. The total ionization yield and fragmentation ratios are presented for a range of wavelengths and intensities, and compared to the changes observed due to a linear chirp variation.
Description: Copyright: 2010 MDPI, Open Access Journal
URI: www.mdpi.com/journal/ijms
http://hdl.handle.net/10204/4361
ISSN: 1422-0067
Appears in Collections:Laser physics and technology
General science, engineering & technology

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