Quantum stereodynamics of the Li+HF(v,j) reactive collision for different initial states of the reagent

Lara, M.; Aguado, Alfredo; Roncero, Octavio; Paniagua, Miguel

doi:10.1063/1.477600

Cited by 67 publications

(112 citation statements)

References 63 publications

(77 reference statements)

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“…Ω is the projection of j on the z-axis, parallel to R, and Ω = 0 for j > 0 corresponds to an angular distribution with a maximum at collinear configurations, while Ω = ±j is a T-shaped configuration. Assuming that the orientation of j do not change significantly in the entrance channel, σ Ω=0 > σ Ω=j indicates that the reaction is favoured for collinear approaches as discussed previously [18,23,24]. For j = 1, this is the case for low energies, E < 0.8 eV .…”

Section: B Effect Of the Initial States Of Reagentsmentioning

confidence: 92%

“…The helicity dependent crosssection are defined as [17,18] (4) with and . J is the absolute value of the total angular momentum and ϵ=±1 is the parity under inversion of coordinates.…”

Section: B Quantum Calculationsmentioning

confidence: 99%

“…To save computational time, for J > 30, complete WP calculations were performed only for some J values, those multiple of 5. For intermediate matrix elements were calculated using the J-shifting interpolation method [12,18].…”

Section: B Quantum Calculationsmentioning

confidence: 99%

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Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions

Zanchet

Roncero

Bulut

2016

Phys. Chem. Chem. Phys.

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State-to-state cross sections for the S + + H 2 (v, j) → SH + (v′, j′) + H endothermic reaction are obtained with quantum wave packet(WP) and quasi-classical (QCT) methods for different initial rovibrational H 2 (v, j) over a wide range of translation energies. Final state distribution as a function of the initial quantum number is obtained and discussed. Additionally, the effect of the internal excitation of H 2 on the reactivity is carefully studied. It appears that energy transfer among modes is very inefficient, that vibrational energy is the most favorable for reaction and rotational excitation significantly enhance reactivity when vibrational energy is sufficient to reach the product. Special attention is also paid on an unusual discrepancy between classical and quantum dynamics for low rotational levels while agreement improves with rotational excitation of H 2 , An interesting resonant behaviour found in WP calculations is also discussed and is associated to the existence of roaming classical trajectories that enhance the reactivity of the title reaction. Finally, a comparison with the experimental results of Stowe et al. [1] for S + + HD and S + +D 2 reactions, finding a reasonably good agreement with those results. I IntroductionSulfur is one of the most abundant elements in space, after H, He, O, C and N. Its relative abundance with respect to H is 10 −5 . However, the relative abundance of all the sulfur containing molecules detected so far in space is several order of magnitudes lower. Sulfur has not being detected in ices in space, and it is therefore concluded that it must be present in highly refractive grains, not yet determined [2,3].The first step in the sulfur chemistry is the formation of its hydride, in neutral or cationic form. SH + can be formed in collisions of atomic S with , but ion is only abundant in cold molecular clouds. The recent detection of SH + in hot regions, such as star formation regions [4], diffuse clouds [5,6], and dense PDRs [7], indicates that there must by other routes * alexandre.zanchet@csic.es. Europe PMC Funders Group Europe PMC Funders Author ManuscriptsEurope PMC Funders Author Manuscripts to form this hydride cation. This low rotational N=1 → 0 transition of SH + ( 3 ∑ − ) was recently measured in the laboratory by Halfen and Ziurys [8].One possible pathway is the (1) reaction. This reaction is endothermic for H 2 (v = 0) by ≈ 0.86 eV [1,9], but it may be the source of SH + when considering vibrationally excited states of H 2 (v ≥ 2), as proposed by Agundez et al. [10].Very recently, a potential energy surface (PES) for the ground quartet electronic state of this system has been calculated, and reaction rate constants were obtained using a quasi-classical trajectory (QCT) method [11]. The rates obtained increase substantially with increasing the initial vibrational state of H 2 , and were used to model SH + fractional abundance as a function of the visual extinction, A v . For A v < 3, there is a notorious increase of the abundance of SH + because at t...

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Section: B Effect Of the Initial States Of Reagentsmentioning

confidence: 92%

“…The helicity dependent crosssection are defined as [17,18] (4) with and . J is the absolute value of the total angular momentum and ϵ=±1 is the parity under inversion of coordinates.…”

Section: B Quantum Calculationsmentioning

confidence: 99%

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Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions

Zanchet

Roncero

Bulut

2016

Phys. Chem. Chem. Phys.

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“…The reaction probabilities for specific values of ⍀ can be summed over J to obtain the helicity-dependent cross sections. 40 The fact that both the reaction probabilities and the helicity-dependent cross sections are larger for ⍀ = 1 implies that the reaction is more favored when the angular momentum j of the HCl reactant is initially parallel to the relative velocity vector k. For J Ͼ 0 the body-fixed xz plane rotates in space. Some more intuitive considerations can be made, however, if we place ourselves in the body-fixed frame.…”

Section: -3mentioning

confidence: 99%

“…Body-fixed Bessel functions were used in the CS approach, as described previously. 40,45 The Gaussian wave packet is initially placed at relatively long distances, around R = 16 Å, because of the long-range character of the PES. In photoinitiated dynamics the initial wave packet is built as described previously.…”

Section: ͑1͒mentioning

confidence: 99%

Collisional and photoinitiated reaction dynamics in the ground electronic state of Ca–HCl

Sanz-Sanz

Avoird

Roncero

2005

The Journal of Chemical Physics

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Ca+ HCl͑ , j͒ reactive collisions were studied for different rovibrational states of the HCl reactant using wave-packet calculations in reactant Jacobi coordinates. A recently proposed potential-energy surface was used with a barrier of Ϸ0.4 eV followed by a deep well. The possibility of an insertion mechanism due to this last well has been analyzed and it was found that once the wave packet passes over the barrier most of it goes directly to CaCl+ H products, which shows that the reaction dynamics is essentially direct. It was also found that there is no significant change in the reaction efficiency as a function of the initial HCl rovibrational state, because CaHCl at the barrier has an only little elongated HCl bond. Near the threshold for reaction with HCl͑ =0͒, however, the reaction shows significant steric effects for j Ͼ 0. In a complementary study, the infrared excitation from the Ca-HCl van der Waals well was simulated. The spectrum thus obtained shows several series of resonances which correspond to quasibound states correlating to excited HCl͑͒ vibrations. The Ca-HCl binding energies of these quasibound states increase dramatically with , from 75 to 650 cm −1 , because the wave function spreads increasingly over larger HCl bond lengths. Thus it explores the region of the barrier saddle point and the deep insertion well. Although also the charge-transfer contribution increases with , the reaction probability for resonances of the =2 manifold, which are well above the reaction threshold, is still negligible. This explains the relatively long lifetimes of these = 2 resonances. The reaction probability becomes significant at = 3. Our simulations have shown that an experimental study of this type will allow a gradual spectroscopic probing of the barrier for the reaction.

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Quasi‐classical trajectory stereodynamics study of the Li + HF(v = 0, j = 0) → LiF + H reaction

Yuan¹,

Zhao²

2009

Int J of Quantum Chemistry

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ABSTRACT:In this work, quasi-classical trajectory (QCT) calculations for the Li ϩ HF (v ϭ 0, j ϭ 0) 3 LiF ϩ H reaction, on the Aguado-Paniagua2-potential energy surface (AP2-PES) constructed by Aguado et al. (Aguado et al., J Chem Phys 1997, 107, 10085), have been performed to study the vector properties of the products. The dihedral angle distribution P( r ) characterizing the k-k-j correlation and the P( r ) distribution characterizing the k-j correlation are calculated and discussed. Furthermore, the angular distribution P( r , r ) of product rotational vectors plotted in polar form in r and r is presented. Finally, the average rotational alignment factor ϽP 2 (cos r )Ͼ is calculated over a collision energy range of 20 -450 meV to investigate the variation of the rotational alignment with collision energy.

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Quantum stereodynamics of the Li+HF(v,j) reactive collision for different initial states of the reagent

Cited by 67 publications

References 63 publications

Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions

Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions

Collisional and photoinitiated reaction dynamics in the ground electronic state of Ca–HCl

Quasi‐classical trajectory stereodynamics study of the Li + HF(v = 0, j = 0) → LiF + H reaction

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Quantum stereodynamics of the Li+HF(v,j) reactive collision for different initial states of the reagent

Cited by 67 publications

References 63 publications

Quantum and quasi-classical calculations for the S+ + H2(v,j) → SH+(v′,j′) + H reactive collisions

Quantum and quasi-classical calculations for the S+ + H2(v,j) → SH+(v′,j′) + H reactive collisions

Collisional and photoinitiated reaction dynamics in the ground electronic state of Ca–HCl

Quasi‐classical trajectory stereodynamics study of the Li + HF(v = 0, j = 0) → LiF + H reaction

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Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions

Quantum and quasi-classical calculations for the S⁺ + H₂(v,j) → SH⁺(v′,j′) + H reactive collisions