Anatomy of an Elementary Chemical Reaction

Alexander, Andrew J.; Zare, Richard N.

doi:10.1021/ed075p1105

Cited by 35 publications

(19 citation statements)

References 32 publications

(41 reference statements)

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“…35 This is to be expected: transitions with small changes in j result primarily from high impact parameter ‘glancing’ trajectories, whereas a large degree of rotational excitations necessitates low impact parameter ‘head-on’ collisions. For j ′ = 5.5, the images and the DCSs show little dependence on the orientation of the NO bond axis.…”

Section: Resultsmentioning

confidence: 98%

Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

et al. 2015

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Section: Resultsmentioning

confidence: 98%

Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

et al. 2015

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“…The differential cross section for a state-to-state reactive molecular collision often exhibits a complicated interference pattern. An important problem, which is discussed in recent reviews, [1][2][3][4][5][6][7][8][9][10][11][12][13] is to analyse this scattering pattern in order to obtain information on the reaction dynamics.…”

Section: Introductionmentioning

confidence: 99%

“…2,[29][30][31][33][34][35][36][37][38] A common observation in the angular distributions of stateto-state reactions is an enhancement of the forward angle scattering, which is often accompanied by oscillations. [1][2][3][4][5][6][7][8][9][10][11][12][13] The semiclassical theory developed in refs. 29 and 30 for zero helicity state-to-state transitions shows that the forward angle scattering is associated with the factor 1/sin y R , where y R is the reactive scattering angle.…”

Section: Introductionmentioning

confidence: 99%

Theory of forward glory scattering for chemical reactions

Connor

2004

Phys. Chem. Chem. Phys.

160

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The theory of forward glory scattering is developed for a state-to-state chemical reaction whose scattering amplitude can be expanded in a Legendre partial wave series. Two transitional approximations are derived that are valid for angles on, and close to, the axial caustic associated with the glory. These are the integral transitional approximation (ITA) and the semiclassical transitional approximation (STA), which is obtained when the stationary phase method is applied to the ITA. Both the ITA and STA predict that the scattering amplitude for glory scattering is proportional to a Legendre function of real degree or, to a very good approximation, a Bessel function of order zero. A primitive semiclassical approximation (PSA) is also derived that is valid at larger angles, away from the caustic direction, but which is singular on the caustic. The PSA demonstrates that glory structure arises from nearside-farside (NF) interference, in an analogous way to the two-slit experiment. The main result of the paper is a uniform semiclassical approximation (USA) that correctly interpolates between small angles, where the ITA and STA are valid, and larger angles where the PSA is valid. The USA expresses the scattering amplitude in terms of Bessel functions of order zero and unity, together with N and F cross sections and phases. In addition, various subsidiary approximations are derived. The input to the theory consists of accurate quantum scattering matrix elements. The theory also has the important attribute that it provides physical insight by bringing out semiclassical and NF aspects of the scattering. The theory is used to show that the enhanced small angle scattering in the F + Hreaction is a forward glory, where v i , j i , m i and v f , j f , m f are initial and final vibrational, rotational and helicity quantum numbers respectively. The forward angle scattering for the H + Dreaction is also analysed and shown to be a forward glory, in agreement with a simpler treatment by D. Sokolovski (Chem. Phys. Lett., 2003, 370, 805), which is a special case of the STA.

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“…As with our previous work, 3-5 the new experiments utilize the photon-initiated reaction technique, 17,[23][24][25][26][27][28][29] and employ Doppler resolved laser induced fluorescence ͑LIF͒ techniques [26][27][28][29] to extract the desired stereodynamical information. The experiments are conducted at a mean collision energy of 143 kJ mol Ϫ1 (ϵ1.48 eV).…”

Section: Introductionmentioning

confidence: 99%

The H+N2O→OH(2ΠΩ,υ′,N′)+N2 reaction: OH rotational angular momentum polarization

Brouard

Gatenby

Joseph

et al. 2000

The Journal of Chemical Physics

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The OH state-resolved angular momentum polarization generated by the H+N2O reaction has been investigated at a mean collision energy of 1.5 eV. The data were obtained under room temperature bulb conditions using 225 nm photolysis of H2S to generate translationally excited H atoms, and employed Doppler-resolved laser induced fluorescence to probe the nascent OH reaction products. The measurements revealed the OH rotational angular momentum, j′, to be aligned in the scattering plane (i.e., in the plane containing the reactant and product relative velocity vectors, k and k′). Furthermore, j′ was found to be preferentially aligned parallel to k′, particularly for lower OH rotational states. Out-of-plane torsional forces have been shown, therefore, to play an important role in generating OH rotation as the fragments separate. The new data are discussed in light of previously published studies of the title reaction, both from our own laboratory, and from those of other workers. Insight into the reaction mechanism is provided by comparison with the photodissociation dynamics of HN3, which helps, in particular, to clarify the origin of the propeller-like OH rotational angular momentum polarization.

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Anatomy of an Elementary Chemical Reaction

Cited by 35 publications

References 32 publications

Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

Theory of forward glory scattering for chemical reactions

The H+N2O→OH(2ΠΩ,υ′,N′)+N2 reaction: OH rotational angular momentum polarization

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