Evidence for steric effect in methyl chloride ionization by metastable argon atoms

Ohoyama, Hiroshi; Kawaguchi, H.; Yamato, Masanori; Kasai, Toshio; Brunetti, Brunetto Giovanni; Vecchiocattivi, Franco

doi:10.1016/s0009-2614(99)01068-4

Cited by 25 publications

(18 citation statements)

References 21 publications

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“…9 the Ar* metastable argon atomic beam is produced by 30 s-pulsed glow discharge of neat Ar supersonic beam expanded from a 1.0 mm diam pulsed valve whose temperature is kept within 120 Ϯ5°C. The pulsed CHCl 3 beam is produced by supersonic expansion at 100 Torr.…”

Section: Methodsmentioning

confidence: 96%

“…[2][3][4][5][6][7][8] Recently, we have performed direct observation of the steric effect in methyl chloride ionization by the metastable argon atom using the hexapole state-selector. 9 In the present study, we extend our exploration for obtaining experimental evidence for steric effect in Ar*( 3 P 2,0 ) ϩCHCl 3 →CHCl 2 ϩ ϩClϩArϩe Ϫ Penning ionization reaction using oriented CHCl 3 molecules. We then discuss the steric opacity function to clarify the reaction mechanism at the molecular level.…”

Section: Introductionmentioning

confidence: 99%

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Direct observation of the steric effect in Penning ionization reaction of Ar*+CHCl3→CHCl2++Cl+e−+Ar

Yamato

Okada

et al. 2000

The Journal of Chemical Physics

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Steric effect in the Penning ionization reaction of Ar*( 3 P 2,0 )ϩCHCl 3 →ArϩCHCl 2 ϩ ϩClϩe Ϫ was directly observed at an average collision energy of 0.13 eV using the oriented CHCl 3 molecular beam. The product CHCl 2 ϩ ions are measured for the H-end, the CCl 3 -end, and sideways orientations. The obtained steric opacity function reveals that the CCl 3 -end orientation is more favorable than the H-end orientation, and the sideways approach is found to be more favorable than the collinear approaches from both ends of the molecule. Furthermore, we confirm the good correlation between Penning ionization anisotropy and the electron density distribution of the 2a 2 HOMO orbital of the CHCl 3 molecule, whose electron cloud is mostly localized around the sideways. These results substantiate the electron exchange mechanism which is commonly accepted for the Penning ionization reaction, where the overlap of projectile atomic and target molecular orbital plays a key role in Penning ionization efficiency.

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Section: Methodsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Direct observation of the steric effect in Penning ionization reaction of Ar*+CHCl3→CHCl2++Cl+e−+Ar

Yamato

Okada

et al. 2000

The Journal of Chemical Physics

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“…For instance, the steric effect in the Ar͑ 3 P͒ϩCH 3 Cl→ArϩCH 3 Cl ϩ ϩe Ϫ reaction was studied in our laboratory by using the electrostatic hexapole method. 11 It was confirmed experimentally that the spatial distribution of the molecular orbital involved in ionization can indeed explain the stereoanisotropy. This result directly suggests that the probability of Penning ionization is controlled by the electron exchange probability that is approximated by the overlap coupling matrix of ⌫ϭ͗ ͉⌽ 3p ͘, where is the molecular orbital and ⌽ 3p the 3p orbital of Ar͑ 3 P).…”

Section: Introductionmentioning

confidence: 90%

“…W(F"r) can be determined from the trajectory simulation of the experimental focusing curve. It can be described using a series of Legendre polynomials 11 W͑F"r͒ϭ ͚ c n P n ͑ F"r͒ ϭ ͚ ͗P n ͑ F"r͒͘ 2nϩ1 2 P n ͑ F"r͒, nϭ0,1,2, . .…”

Section: Methodsmentioning

confidence: 99%

Nuclear-excited Feshbach resonance in the Ar(3P)+CH3Br Penning ionization reaction under orientation and velocity specified collisions

Okada

Ohoyama

Kasai

2002

The Journal of Chemical Physics

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The collision-energy and orientation-angle-resolved Penning ionization cross section was determined for the Ar͑ 3 P͒ϩCH 3 Br reaction by using an oriented beam and a time-of-flight measurement. A remarkable resonance-type structure in the Penning ionization cross section is recognized in the collision energy dependence at fixed molecular orientations, which is very similar to the one we previously observed in the Ar͑ 3 P͒ϩCH 3 Cl reaction. This resonance-type structure could be interpreted as a new type nuclear-excited Feshbach resonance where the branching to competitive neutral dissociation channel is enhanced due to the formation of vibrationally excited CH 3 Br Rydberg states.

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“…[1] A plethora of data is available for the PI channel. [2][3][4][5][6][7] Quantities of physical relevance such as the state specific total ionization cross sections and electron angular distributions have been obtained, yielding further insight into the energy transfer process. [8-11, 13, 14] Later, it was found that PI experiments are ideally suited for use in very low collision energy experiments.…”

Section: Introductionmentioning

confidence: 99%

Energy Dependent Stereodynamics of theNe(P32)+Ar<

et al. 2017

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The stereodynamics of the Ne( 3 P2)+Ar Penning and Associative ionization reactions have been studied using a crossed molecular beam apparatus. The experiment uses a curved magnetic hexapole to polarise the Ne( 3 P2) which is then oriented with a shaped magnetic field in the region where it intersects with a beam of Ar( 1 S). The ratios of Penning to associative ionization were recorded over a range of collision energies from 320 cm −1 to 500 cm −1 and the data was used to obtain Ω state dependent reactivities for the two reaction channels. These reactivities were found to compare favourably to those predicted in the theoretical work of Brumer et al.

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Evidence for steric effect in methyl chloride ionization by metastable argon atoms

Cited by 25 publications

References 21 publications

Direct observation of the steric effect in Penning ionization reaction of Ar*+CHCl3→CHCl2++Cl+e−+Ar

Direct observation of the steric effect in Penning ionization reaction of Ar*+CHCl3→CHCl2++Cl+e−+Ar

Nuclear-excited Feshbach resonance in the Ar(3P)+CH3Br Penning ionization reaction under orientation and velocity specified collisions

Energy Dependent Stereodynamics of theNe(P32)+Ar<

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