Predissociation dynamics of D2 + hv → D(1s1/2) + D(2p1/2,3/2, 2s1/2) revealed by the spin-orbit state resolved fragment branching ratios and angular distributions

Wang, Jie; Mo, Yuxiang

doi:10.1063/1.5087865

Cited by 8 publications

(1 citation statement)

References 28 publications

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“…Moreover, it is possible to polarize the reactants bond-axis or rotational angular momentum, so it can be achieved some control into the relative geometry of the reactants before their interactions. For the non-familiar reader that may sound utopia, but several groups have succeeded in carrying out such experiments using either optical alignment methods, [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] brute force through intense laser fields [17][18][19][20][21][22][23][24][25][26][27][28], or using static orienting fields in tandem with hexapole state selection. [29][30][31][32][33][34][35] Based on the experimental set-up by Kandel et al, [11] in a series of articles we have suggested a hypothetic crossed-beam experiment for atom-diatom reactions where the diatom (in this case D 2 ) is prepared in a |v = 0, j = 2, m = 0 state, where v, j, and m are the vibrational, rotational and magnetic quantum number.…”

Section: Introductionmentioning

confidence: 99%

How reactant polarization can be used to change the effect of interference on reactive collisions

Jambrina

Menéndez

Zanchet

et al. 2019

Phys. Chem. Chem. Phys.

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It is common knowledge that integral and differential cross sections (DCSs) are strongly dependent on the spatial distribution of the molecular axis of the reactants. Hence, by controlling the axis distribution, it is possible to either promote or hinder the yield of products into specific final states or scattering angles. This idea has been successfully implemented in experiments by polarizing the internuclear axis before the reaction takes place, either by manipulating the rotational angular distribution or by Stark effect in the presence of an orienting field. When there is a dominant reaction mechanism, characterized by a set of impact parameters and angles of attack, it is expected that a preparation that helps the system to reach the transition state associated with that mechanism will promote the reaction, whilst a different preparation would generally impair the reaction. However, when two or more competing mechanisms via interference contribute to the reaction into specific scattering angles and final states, it is not evident which would be the effect of changing the axis preparation. To address this problem, throughout this article we have simulated the effect that different experimental preparations have on the DCSs for the H + D2 reaction at relatively high energies, for which it has been shown that several competing mechanisms give rise to interference that shapes the DCS. To this aim, we have extended the formulation of the polarization dependent DCS to calculate polarization dependent generalized deflection functions of ranks greater than zero. Our results show that interference are very sensitive to changes in the internuclear axis preparation, and that the shape of the DCS can be controlled exquisitely. * pjambrina@usal.es † aoiz@ucm.es

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Section: Introductionmentioning

confidence: 99%

How reactant polarization can be used to change the effect of interference on reactive collisions

Jambrina

Menéndez

Zanchet

et al. 2019

Phys. Chem. Chem. Phys.

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Photodissociation of HCl in the photon energy range 14.6–15.0 eV: Channel-resolved branching ratios and fragment angular distributions

Wang

2020

The Journal of Chemical Physics

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For the HCl molecule, four photodissociation channels are open in the excitation energy region 14.6–15.0 eV: H(2s) + Cl(2P3/2), H(2p) + Cl(2P3/2), H(2s) + Cl(2P1/2), and H(2p) + Cl(2P1/2). We measured the fragment angular distributions and the branching ratios of the four dissociation channels by using the extreme ultraviolet laser pump and UV laser probe, delay-time-curve, and velocity map imaging methods. The channel-resolved fragment angular distributions and fragment yield spectra show that various Rydberg states (superexcited states) contribute to the absorption cross sections, including the [A2Σ+]4pσ, [A2Σ+]4pπ, [A2Σ+]3dσ, [A2Σ+]3dπ, and [A2Σ+]5sσ states. Most of the H(2s) + Cl(2P1/2) channels correlate with the 1Σ+ states, while the other channels correlate with mixing excitations of the 1Σ+ and 1,3Π states. The channel branching ratios are dependent on the excitation energies. When the four channels are open, the channel branching ratios of H(2s) + Cl(2P3/2) and H(2p) + Cl(2P1/2) are small. Based on the recent ab initio potential energy curves, the Rydberg states converging to the ion-core A2Σ+ are proposed to be predissociated by the nuclear vibrational continua of the Rydberg states converging to the ion-core X2Π.

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Observation of rotationally dependent fine-structure branching ratios near the predissociation threshold N(2D5/2,3/2) + N(2D5/2,3/2) of 14N2

Jiang

Gao

2022

The Journal of Chemical Physics

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Photofragment spin-orbit fine-structure branching ratios have long been predicted to depend on rotational quantum number J ′ by theory near the dissociation thresholds of several diatomic molecules, while this has rarely been observed in any photodissociation experiments yet. Here, we measured the fine-structure branching ratios N(2D5/2)/N(2D3/2) produced in the N(2D5/2, 3/2)+N(2D5/2, 3/2) channel at the 1+( v=20) state of 14N2 by using our vacuum ultraviolet (VUV)-pump-VUV-probe time-sliced velocity-mapped ion imaging setup. It is found that 14N2 almost exclusively dissociates into the spin-orbit channel N(2D5/2)+N(2D3/2) at low rotational levels, and gradually approaches the statistical or diabatic limit by distributing all possible spin-orbit channels at higher rotational levels. The strongly rotationally dependent fine-structure branching ratios should be due to the increasing strength of nonadiabatic Coriolis interaction among various dissociative states in the so called "recoupling zone" as J ′ increases. They are supposed to provide unprecedented information on the near threshold photodissociation dynamics of 14N2.

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Predissociation dynamics of D2 + hv → D(1s1/2) + D(2p1/2,3/2, 2s1/2) revealed by the spin-orbit state resolved fragment branching ratios and angular distributions

Cited by 8 publications

References 28 publications

How reactant polarization can be used to change the effect of interference on reactive collisions

How reactant polarization can be used to change the effect of interference on reactive collisions

Photodissociation of HCl in the photon energy range 14.6–15.0 eV: Channel-resolved branching ratios and fragment angular distributions

Observation of rotationally dependent fine-structure branching ratios near the predissociation threshold N(2D5/2,3/2) + N(2D5/2,3/2) of 14N2

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