Several Experiments on Rare Gas Clusters and Nanoparticles
Some experimental work on rare gas clusters formed in supersonic jets and the development of high volume production of nanoparticles by laser ablation of microparticles (LAM) either on plates or in jets will be presented in this dissertation. Experiments on rare gas clusters in supersonic jets show that the size distribution of clusters formed in a pulsed jet varies for different part of the jet. It is also shown that helium clusters are attached on the xenon dimers at the later part of the jet pulse. These attached helium clusters have strong influence on the fluorescence from xenon dimers when the xenon dimers are excited. Fluorescence from excimer are observed for the xenon dimer states correlating to Xe^* 6p (1/2) _0 and 5d (1/2) _1. Fluorescence from predissociated states are observed for the xenon dimer states correlating to Xe^* 6p (1/2) _0, 5d (1/2) _1 and 6p (3/2) _2. No fluorescence from the xenon dimer state correlating to 6p (5/2) _2 has been observed. The second part of this dissertation describes the development of high volume production of nanoparticles by laser ablation of microparticles (LAM) either on plates or in jets. It shows that nearly monodispersed nanoparticles with sizes range from 20 nm to 200 nm can be produced by this method for both dielectric material (glass) and metal material (gold). In the experiments, the microparticles are ablated by pulsed excimer laser with wavelength 249 nm; the nanoparticles are collected on the silicon wafers and pictured under SEM; the size distribution of nanoparticles is then analyzed by an image processing software developed by NIH. Comparing to other synthesis methods for nanoparticles, this method has the potential to be scaled up for industrial production of monodispersed nonagglomerated high purity nanoparticles for different kinds of materials.
- Pub Date:
- November 1995
- Physics: Molecular; Engineering: Chemical