Differential cross sections for H+D2→HD (v′=2, J′=0,3,5)+D at 1.55 eV

Abstract

Product state(s)-resolved differential cross section of the reaction O ( 1 D)+ HD→OH (v,j)+ D The photoloc technique with core extraction of the nascent product laboratory speed distribution in a Wiley-McLaren time-of-flight spectrometer has been used to measure differential cross sections for the reaction HϩD 2˜H D (vЈϭ2, JЈϭ0,3,5)ϩD at collision energies ϳ1.55 eV. We find that the peak of each angular distribution shifts from complete backward scattering toward side scattering as the rotational excitation of the product increases. We found the same trend in our previous study of HϩD 2˜H D (vЈϭ1, JЈϭ1,5,8)ϩD at ϳ1.70 eV. We conclude that the same type of correlation exists between impact parameter and rotational quantum number in both product vibrational manifolds. Further analysis of the HD (vЈϭ2, JЈ) differential cross section data reveals, however, a clear tendency of this vibrational manifold to scatter sideways at lower JЈ than HD(vЈϭ1, JЈ). Within the framework of a line-of-centers model with nearly elastic specular scattering, this result implies that smaller impact parameters lead to more vibrationally excited products.

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

“…The instrumental calibration parameters have been described in detail in a previous publication, and therefore the details will be omitted. 56 Each laboratory velocity of the HD product corresponds to a unique scattering angle in the center-of-mass frame according to the law of cosines…”

“…56 Here, we restrict ourselves to a brief account of the apparatus and the salient features of the experimental method followed in this particular work.…”

“…Typical gas pulses, as measured by monitoring D 2 E, F 1 ⌺ g ϩ -X 1 ⌺ g ϩ , and HBr H 1 ⌺ ϩ -X 1 ⌺ ϩ (2ϩ1) REMPI ion signals, are approximately 600 s. The pulsed solenoid valve injects the gas pulse into the extraction region of a Wiley-McLaren time-of-flight spectrometer 56 at nominal pressures of 5.0-10.0 ϫ10 Ϫ6 Torr. It is in this region that reaction takes place.…”

A fully state- and angle-resolved study of the H+HD→D+H2 reaction: Comparison of a molecular beam experiment to ab initio quantum reaction dynamics

“…We also note there have been other important recent advances in the molecular beam methodology that have allowed improvements in the resolution and facility of reactive scattering data. 5,[7][8][9] On the theory side, a potential energy surface of Boothroyd et al, 10 the BKMP2-PES, is apparently globally accurate to within 30 cm Ϫ1 , which is likely to be sufficient to model the reaction dynamics. Anderson and co-workers have recently developed an even more accurate surface.…”

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).…”