comparative study of the dissociative ionization of 1,1,1 trichloroethane using nanosecond and femtosecond laser pulses比较研究离解电离的1,1,- 1三氯乙烷使用纳秒和飞秒激光脉冲.pdf

Int. J. Mol. Sci. 2010, 11, 1114-1140; doi:10.3390/ijm OPEN ACCESS International Journal of Molecular Sciences ISSN 1422-0067 /journal/ijms Article Comparative Study of the Dissociative Ionization of 1,1,1-Trichloroethane Using Nanosecond and Femtosecond Laser Pulses Anton du Plessis 1,2,*, Christien Strydom 3 and Lourens Botha 1,2 1 CSIR National Laser Centre, PO Box 395, Meiring Naude Road, Pretoria 0001, South Africa 2 Physics Department, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa 3 Chemical Resource Beneficiation, North-West University, Private Bag X6001, Potchefstroom 2520, South Africa * Author to whom correspondence should be addressed; E-Mail: adplessis2@csir.co.za; Tel.: +27-12-841-4504; Fax: +27-12-841-3152. Received: 28 January 2010; in revised form: 25 February 2010 / Accepted: 26 February 2010 / Published: 17 March 2010 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