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Crossed molecular beams kinetics: SnI and SnCl recoil velocity spectra from Sn+CH/sub 3/I,n-C/sub 3/H/sub 7/I, and CCl/sub 4/ and a lower limit for D/sup 0//sub 0/(SnI)

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:6733638

Laboratory (LAB) angular and time-of-flight (TOF) recoil velocity spectra of SnI and SnCl products formed by crossing an effusive Sn beam with CH/sub 3/I, n-C/sub 3/H/sub 7/I, and CCl/sub 4/ nozzle beams have been measured in a molecular beam apparatus equipped with an electron bombardment ionizer--quadrupole mass filter detector unit. Product center of mass (c.m.) recoil angle and energy distributions have been fit to the data by convoluting the c.m...-->..LAB transformation equations over measured speed distributions for both beams and the instrumental TOF response function. The Sn+CH/sub 3/I and n-C/sub 3/H/sub 7/I reactions proceed via a direct interaction mechanism which favors scattering of SnI into the backward c.m. hemisphere (backward scattering denotes a reversal in Sn-atom direction during the reactive encounter). The SnCl from Sn+CCl/sub 4/ is scattered predominantly sideways, probably also via a direct reaction mechanism. The Sn+CH/sub 3/I reaction produces a more sharply backward peaked SnI c.m. product angular distribution with higher product recoil energies than does the Sn+n-C/sub 3/H/sub 7/I reaction. All of these reaction characteristics are strikingly similar to the best experimental information which is available for the analogous alkali atom reactions. Qualitative observations are also reported on the relative reactivities of Sn with CH/sub 3/I,n-C/sub 3/H/sub 7/I, CCl/sub 4/,i-C/sub 3/H/sub 7/I, CH/sub 3/Br, CF/sub 3/Br, C/sub 2/Cl/sub 4/, and SF/sub 6/. A rigorous lower limit for the Sn--I bond energy is also established, D/sup 0//sub 0/(SnI) > or =230 kJ/mole.

Research Organization:
Ames Laboratory--USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011
OSTI ID:
6733638
Journal Information:
J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 69:6; ISSN JCPSA
Country of Publication:
United States
Language:
English