MOLECULAR BEAM REACTION OF K ATOhis WITH SIDEWAYS ORIENTED CF31

Reactions of alkzdi met& have plrryed a central role in the eluci&tion of the Jynamics of cherniczf rcx[ions [I-31. and marly tktturcs of these reactions law been qualitatively rurrclrrtcd using “impulsive” or photodissociation mod& based on ;tn eIectron tmnsfer ntcchrtnism originally proposed by Pohnyi and Magce [-II_ _-\ccrurding to this mechanism. an electron is transferred from the cusiiy-ion&d ;rIkdi metal to 3 specks of high electron atXnity_ typic+ 4 imIw~cn-cont;lining molccuIc_ The ultimate details of reaction, such as cross section, energy dispou1. and zmgdx distribution of products_ depend on the stability of the nascent molcculsr ion_ This mcch~nism was inrokcd in a previous invesrigation of the reaction of K atoms with oriented CF3 I [5[_ Ki was fiiuud to be satrered forwxd in the centcruf-mzss (cm.) s> stem when the K stem attacked at the brrcksidc. or CF3. end of the mokcuk (“tsiW orientatiat). whcrras ths KI was satrcred bsckwnd in the cm. t&n tbc other, --hrrJs”_ orienrarion_ It was sugetcd tfxn ifrhc CFjtion furmcd by cIcctroti transfer were in 3 repubi~e ekctronic sf3fe. tIte ion would Iitcrzdiy e\pIodc, sendicg the Iand CF, moieties along the instantaneous direction of the moIccular axis_ This predicted forward sczttcring for the “tails” orientation. and backward scattering for the “‘heads” orientation, and agreed scmiquzntitatively with experiment. To test this hypothesis we have oriented the CF,I moIecuics perpendicular to the relative vetocity (i-e-, “sideways*‘), so that the I end of the molecule an be directed towards or away from tIte detector, depending on the polrrrity of the applied electric field. This changes the view of the reaction as seen by the detector without changing the rczction dyrzamicr. As expected, the ang_dar distribution of sattcrcd mo%culcs is drastically changedThe result is in rough agreement with predictions of the ckctron-trasfcr model, but discrepancies still exist.