328534-16-3Relevant academic research and scientific papers
On the efficient generation of Arn-SH free-radical clusters via ultraviolet photolysis of closed-shell Arn-H2S complexes
Mackenzie,Votava,Fair,Nesbitt
, p. 5149 - 5158 (1999)
Detailed investigations are described for the generation of open-shell radical complexes formed by unimolecular photolysis of closed-shell van der Waals precursors. As a specific test case, ultraviolet photolysis of slit-jet cooled Arn-H2S (n≤2) complexes at both 248 and 193 nm are shown to yield Ar-SH and Ar2-SH radical cluster species with surprisingly high efficiencies. Analysis of the laser induced fluorescence (LIF) spectra indicates that the radical complexes are produced with extensive van der Waals stretch/bend and overall rotational excitation, which is consistent with a simple ballistic model of the dissociation dynamics. The LIF spectra obtained as a function of expansion distance downstream provide clear evidence for remarkably efficient cooling of the newly formed radical cluster species by low-energy collisions with jet-cooled inert gas atoms at ≈10 K. Spectrally resolved Ar-SH and Ar2-SH LIF signals have been investigated as a function of Ar composition, which yields information on relative branching ratios for fragmentary (e.g., Ar2-H2S→Ar-SH+H+Ar) and nonfragmentary (e.g., Ar2-H2S→Ar2-SH+H) photolysis events.
