Nano particles are of great interest to science and industry because of their extraordinary biological and physical properties. Detection of nano particles is important both for environmental protection and as a diagnostic during the development of novel production methods. Femtosecond laser spectrometry has the potential to play a part in both of these applications. In the lab we are using femtosecond laser pulses to create polyynes (carbon chains caped by hydrogen atoms). Using a newly constructed time of flight mass spectrometer we have been able to measure the polyynes produced form solvent molecules and the fragmentation of molecules such as Octane and Benzene, which in liquid phase combine to generate chains as large as fourteen carbon atoms long.
Students
Asif Zaidi PhD recently completed.
Apparatus
Time of Flight (TOF) mass spectrometer.
Collaborators
Walt Duley, Mike Weslowski, Anming Hu Xiquan Fu
Recent Publications
- Time of flight mass spectrometry of polyyne formation in the irradiation of liquid alkanes with femtosecond laser pulses A.A. Zaidi, A. Hu, M.J. Wesolowski, X. Fu, J.H. Sanderson, Y. Zhou, W.W. DuleyCarbon, Volume 48, Issue 9, August 2010, Pages 2517-2520
- Direct synthesis of polyyne molecules in acetone by dissociation using femtosecond laser irradiation A. Hu, J. Sanderson, A.A. Zaidi, C. Wang, T. Zhang, Y. Zhou, W.W. DuleyCarbon, Volume 46, Issue 13, November 2008, Pages 1823-1825
Related Images
The Ion extraction region before it is put into the vacuum chamber the detector is at the other end approximately one meter away.
The TOF spectrum of octane shows the peaks of many small pollyne molecules (CnH2 (n=2)) generated in the laser induced break up.
From the TOF it is possible to determine the charge to mass ratio and so identify the molecular fragment ions.