Differential cross sections for H+D2→HD(v′=1, J′=1,5,8)+D at 1.7 eV

Abstract

Differential cross section polarization moments: Location of the D-atom transfer in the transition-state region for the reactions Cl+C 2 D 6 →DCl (v ′ =0,J ′ =1)+ C 2 D 5 and Cl+CD 4 →DCl (v ′ =0,J ′ =1)+ CD 3 A 1:4 mixture of HBr and D 2 is expanded into a vacuum chamber, fast H atoms are generated by photolysis of HBr ca. 210 nm, and the resulting HD (vЈ, JЈ) products are detected by (2ϩ1) resonance-enhanced multiphoton ionization ͑REMPI͒ in a Wiley-McLaren time-of-flight spectrometer. The photoloc technique allows a direct inversion of HD (vЈ, JЈ) core-extracted time-of-flight profiles into differential cross sections for the HϩD 2 →HD(vЈϭ1, JЈϭ1,5,8)ϩD reactions at collision energies ca. 1.7 eV. The data reveal a systematic trend from narrow, completely backward scattering for HD (vЈϭ1, JЈϭ1) toward broader, side scattering for HD (vЈϭ1, JЈϭ8). A calculation based on the line of centers model with nearly elastic specular scattering accounts qualitatively for the observations.

The observation of quantum bottleneck states

“…Althorpe et al [38,39] and Zare and co-workers [47] have investigated the dynamics of the H þ D 2 reaction using an approach that also combined theoretical and experimental efforts. The experiments were carried out using the PHOTOLOC (photo-initiated reaction analysed via the law of cosines) technique [48] with a (2 þ 1) REMPI time-of-flight detection scheme. The experiment permitted the determination of the DCS at a number of collision energies, although some angular averaging was implicit in the results because of the nature of the PHOTOLOC scheme.…”

New Scheme for Measuring the Angular Momentum Spatial Anisotropy of Vibrationally Excited H2 via the I 1Πg State

“…A detailed description of the experiment has already been given by Zare and coworkers [18,29]. We limit ourselves to highlighting those elements relevant to the present study.…”

“…The mechanism for vibrational excitation of hydrogen is thought to proceed by molecular dissociation on the hot-filament surface followed by recombination, mostly on Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 6/12/15 8:07 PM the chamber walls [44Ϫ46]. We have used this source of vibrationally excited hydrogen molecules and isotopomers (HD and D 2 ) routinely in our reactive scattering experiments to locate the spectroscopic transitions of particular HD(v′,J′) quantum states [29].…”

The Hydrogen Games and Other Adventures in Chemistry

“…By the photoloc technique, we obtained differential cross sections for a number of product states of the hydrogen atom-hydrogen molecule bimolecular exchange reaction (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40). Further significant improvements involved the use of a position-sensitive detector (41).…”