Lawrence Berkeley National Laboratory
Particle formation from pulsed laser irradiation of soot aggregates studied with a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope
- Author(s): Michelsen, HA
- Tivanski, AV
- Gilles, MK
- Van Poppel, LH
- Dansson, MA
- Buseck, PR
- et al.
Published Web Locationhttps://doi.org/10.1364/AO.46.000959
We investigated the physical and chemical changes induced in soot aggregates exposed to laser radiation using a scanning mobility particle sizer, a transmission electron microscope, and a scanning transmission x-ray microscope to perform near-edge x-ray absorption fine structure spectroscopy. Laser-induced nanoparticle production was observed at fluences above 0.12 J/cm2at 532 nm and 0.22 J/cm2at 1064 nm. Our results indicate that new particle formation proceeds via (1) vaporization of small carbon clusters by thermal or photolytic mechanisms, followed by homogeneous nucleation, (2) heterogeneous nucleation of vaporized carbon clusters onto material ablated from primary particles, or (3) both processes. © 2007 Optical Society of America.