MOLECULAR BEAM REACTIONS OF ORIENTED MOLECULES (TRIFLUOROMETHYL BROMIDE, POTASSIUM)

[摘要] A beam of oriented CF(,3)Br molecules is prepared by passing a randomly oriented beam through an appropriate series of inhomogeneous and homogeneous electric fields. An atomic K beam crosses the beam of oriented CF(,3)Br and the angular distribution of the reactively scattered KBr is measured with a differential surface ionization detector. The ;;heads;; orientation (Br end closest to the incoming K) is about three-fold more reactive than the ;;tails;; orientation. The KBr is scattered backwards in the ;;heads;; orientation and forward in the ;;tails;; orientation, qualitatively consistent with a ;;harpoon;; type of mechanism in which the orientation affects either the electron jump or the breakup of the dissociating negative ion. A new apparatus has been constructed which uses a seeded supersonic nozzle source to produce the oriented molecular beam. The new source is characterized by measuring the velocity distributions of various seeded beams using the time-of-flight technique. The state-selecting properties of the inhomogeneous hexapole field are characterized by measuring the transmission of the field for seeded beams of CF(,3)Br, CF(,3)I, and CH(,3)Cl.

[发布机构] Rice University