Space focusing and mass selection of transition-metal-chlorine and -sulfur clusters generated through laser ablation
Date
2001
Authors
Yu, Yongzhi
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Abstract
The goal of this study was to develop a laser ablation-TOF mass spectrometer system suited to the generation of transition metal -chlorine and -sulfur clusters.
A detailed characterization of the plasma generated by laser ablation was accomplished. Positive clusters were shown to have a slower original flight speed than negative clusters from the same source. The approximate time window during which clusters reached the repeller with the maximum density was measured as well.
A functional triggered TOF-Mass spectrometer was built with adjustable space focusing parameters. This setup works to space focus the positive or negative clusters generated by the laser ablation. The optimized mass resolution this setup can provide is about 300. A functional mass gate was built. The mass gate can isolate a particular mass peak with about 95% purity for clusters with flight times that differ by 1.1 µs.
Many ionic transition metal-chlorine and -sulphur clusters were synthesized and identified, and a systematic survey of the transition metal-chlorine clusters was conducted. Trends were evident in the formation of negative clusters that can be explained by a simple building block model. To a lesser extent, the building block model can be applied to some of the positive clusters. The formation of transition metal -sulphur clusters was far more complicated.