Stereodynamics investigation of F + HO → HF + O(1D) on the ground singlet potential energy surface by means of the quasi-classical trajectory method

2014 ◽  
Vol 92 (3) ◽  
pp. 250-256 ◽  
Author(s):  
Dan Zhao ◽  
Xiaohu He ◽  
Wei Guo

The stereodynamics calculation of F + HO → HF + O(1D) was carried out using the quasi-classical trajectory method on the 11A′ potential energy surface provided by Gomez-Carrasco et al. (Chem. Phys. Lett. 2007, 435, 188). The effect of the collision energy, isotopic substitution, and different initial ro-vibrational states on the reaction is discussed. It is found that for the initial ground state of HO (v = 0, j = 0), the degree of the forward scattering and the product polarizations remarkably change as the collision energy varies. Isotopic effect leads to the increase of alignment and decrease of orientation of product rotational angular momentum. Moreover, the P(θr) distribution and P(φr) distribution change noticeably by varying the initial vibrational number. The initial vibrational excitation plays a more important role in the enhancement of alignment and orientation distribution of j′ for the title reaction. Although the influence of the initial rotational excitation effect on the aligned and oriented distribution of product is not stronger than that of the initial vibrational excitation effect, the initial rotational excitation makes the alignment of the product rotational angular momentum decrease to some extent. The probabilities show that the reactivity of the title reaction strongly depends on the initial vibrational state.

2011 ◽  
Vol 10 (04) ◽  
pp. 401-410
Author(s):  
TAO WANG ◽  
XIANGYANG MIAO

The stereodynamics of the title reaction based on the ground 2A′ potential energy surface (PES) has been investigated using the method of the quasi-classical trajectory (QCT) at different collision energies (23 kcal/mol, 35 kcal/mol and 46 kcal/mol). The vector properties of the angular momentum (described by the distribution of K - J′P(θr), the dihedral angle distribution of K - K′ - J′P(φr) and the angular distribution P(θr, ϕr)) and the four PDDCSs [(2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21-/dωt)] of the product LiF at each collision energy have been presented, respectively. Further, the collision energy effects on the behavior of the product LiF have been discussed and studied.


2011 ◽  
Vol 89 (10) ◽  
pp. 1283-1288
Author(s):  
Li-hua Kang ◽  
Shan-zheng Zhang ◽  
Mingyuan Zhu ◽  
Bin Dai

The stereodynamics of the title reaction on the ab initio1A′ potential energy surface (PES) (B. Bussery-Honvault, P. Honvault, and J.-M. Launay. 2001. J. Chem. Phys. 115: 10701) at a collision energy of 16 kJ/mol have been studied using quasi-classical trajectory (QCT) method. Vector properties including angular momentum alignment parameters and four polarization-dependent differential cross sections (PDDCS) of the product CH are presented. Furthermore, the influence of reagent vibrational and rotational excitations on the product vector properties have also been studied in the present work. The calculated results indicate that the angle distributions of the CH product are mainly dominated by backward–forward scattering.


2014 ◽  
Vol 13 (01) ◽  
pp. 1450002
Author(s):  
Ruifeng Lu ◽  
Zhenyu Xu ◽  
Yunhui Wang

The quasi-classical trajectory method has been employed to investigate the initial vibrational and rotational effects of the title reaction on an improved ab initio potential energy surface for the 11A′ state. Meanwhile, isotopic effect has also been studied at collision energy of 19 kcal/mol. The product rotational alignment factor 〈P2(j′ • k)〉, angular distributions of P(ϕr), P(θr) and the generalized polarization dependent differential cross-sections have been calculated. The- results show that the reagent vibrational excitation generally strengthens the product alignment perpendicular to the reagent relative velocity vector k and affects the product scattering preference, and the rotational excitation has the same trend from j = 0 to 2 except for the higher excitation of j = 3. Further, the substitution of atom H with D leads to a stronger product alignment while changes some stereodynamical properties subtly.


2009 ◽  
Vol 08 (06) ◽  
pp. 1177-1184 ◽  
Author(s):  
QIANG WEI ◽  
VICTOR WEI-KEH WU ◽  
BO ZHOU

The stereodynamics of the title reaction on the ground 1 1A′ potential energy surface (PES) has been studied using quasi-classical trajectory (QCT) method. Collision energy of 6.4 kcal/mol is considered, and vector properties including angular momentum alignment distributions and polarization-dependent differential cross-sections (PDDCS) of the product OH are presented. Furthermore, the influence of reagent rotational excitation and vibrational excitation on the product vector properties has also been studied in the present work. The results indicate that the distribution of the P(θr) and P(ϕr) are sensitively affected by the rotational and vibrational excitation. The rotational excitation decreases the degree of alignment and orientation, while vibrational excitation increases the degree of alignment and orientation. The PDDCS (2π/σ)(dσ20/dωt) and (2π/σ)(dσ22+/dωt) are sensitively influenced by rotational and vibrational excitations, while the PDDCS ((2π/σ)(dσ00/dωt)) and (2π/σ)(dσ21-/dωt) are not. The preference of forward scattering has been found from the results of PDDCS ((2π/σ)(dσ00/dωt)), which is in good agreement with the experimental results.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 994
Author(s):  
Joaquin Espinosa-Garcia ◽  
Cipriano Rangel ◽  
Moises Garcia-Chamorro ◽  
Jose C. Corchado

Based on a combination of valence-bond and molecular mechanics functions which were fitted to high-level ab initio calculations, we constructed an analytical full-dimensional potential energy surface, named PES-2020, for the hydrogen abstraction title reaction for the first time. This surface is symmetrical with respect to the permutation of the three hydrogens in ammonia, it presents numerical gradients and it improves the description presented by previous theoretical studies. In order to analyze its quality and accuracy, stringent tests were performed, exhaustive kinetics and dynamics studies were carried out using quasi-classical trajectory calculations, and the results were compared with the available experimental evidence. Firstly, the properties (geometry, vibrational frequency and energy) of all stationary points were found to reasonably reproduce the ab initio information used as input; due to the complicated topology with deep wells in the entrance and exit channels and a “submerged” transition state, the description of the intermediate complexes was poorer, although it was adequate to reasonably simulate the kinetics and dynamics of the title reaction. Secondly, in the kinetics study, the rate constants simulated the experimental data in the wide temperature range of 25–700 K, improving the description presented by previous theoretical studies. In addition, while previous studies failed in the description of the kinetic isotope effects, our results reproduced the experimental information. Finally, in the dynamics study, we analyzed the role of the vibrational and rotational excitation of the CN(v,j) reactant and product angular scattering distribution. We found that vibrational excitation by one quantum slightly increased reactivity, thus reproducing the only experimental measurement, while rotational excitation strongly decreased reactivity. The scattering distribution presented a forward-backward shape, associated with the presence of deep wells along the reaction path. These last two findings await experimental confirmation.


2011 ◽  
Vol 89 (6) ◽  
pp. 650-656 ◽  
Author(s):  
Juan Zhao

The quasi-classical trajectory (QCT) calculations for the title reaction were carried out using the recently developed, accurate potential energy surface (PES) of the [Formula: see text] singlet state of the OHF system The integral cross section and the product rotational alignment factor [Formula: see text] were calculated as a function of collision energy. In addition, I discovered the effect of isotopic substitution on stereodynamics for the title reaction, and the influence of the rotation excitation of the reagent on stereodynamics is also presented. Both the scalar and vector properties of the reaction O(1D) + HF → OH + F(2P) are studied in this paper. It was found that the reaction is mainly controlled by an indirect reaction mechanism, and that the deep noncollinear insertion HOF well has a great impact on the dynamics of the reaction. The conclusions drawn in this paper will draw from references to similar reactions, and provide a theoretical foundation for related experiments.


2010 ◽  
Vol 88 (5) ◽  
pp. 453-457 ◽  
Author(s):  
Lihua Kang ◽  
Bin Dai

Quasi-classical trajectory (QCT) calculations of total reaction probabilities and vibrationally state-resolved reaction probabilities at total angular momentum J = 0 as a function of collision energy for the C(1D) + H2 (v = 0, j = 0) reactions have been performed on an ab initio potential-energy surface [ J. Chem. Phys. 2001, 115, 10701]. In addition, the integral cross sections as a function of collision energy have been carried out for the same reaction. The product rotational alignments have also been calculated, which are almost invariant with respect to collision energies.


2012 ◽  
Vol 90 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Ningjiu Zhao ◽  
Yufang Liu

In this work, we employed the quasi-classical trajectory (QCT) method to study the vector correlations and the influence of the reagent initial rotational quantum number j for the reaction He + T2+ (v = 0, j = 0–3) → HeT+ + T on a new potential energy surface (PES). The PES was improved by Aquilanti co-workers (Chem. Phys. Lett. 2009. 469: 26–30). The polarization-dependent differential cross sections (PDDCSs) and the distributions of P(θr), P([Formula: see text]r), and P(θr, [Formula: see text]r) are presented in this work. The plots of the PDDCSs provide us with abundant information about the distribution of the product angular momentum polarization. The P(θr) is used to describe the correlation between k (the relative velocity of the reagent) and j′ (the product rotational angular momentum). The distribution of dihedral angle P([Formula: see text]r) shows the k–k′–j′ (k′ refers to the relative velocity of the product) correlation. The PDDCS calculations illustrate that the product of this reaction is mainly backward scatter and it has the strongest polarization in the backward and sideways scattering directions. At the same time, the results of the P([Formula: see text]r) demonstrate that the product HeT+ tends to be oriented along the positive direction of the y axis and it tends to rotate right-handedly in planes parallel to the scattering plane. Moreover, the distribution of the P(θr) manifests that the product angular momentum is aligned along different directions relative to k. The direction of the product alignment may be perpendicular, opposite, or parallel to k. Moreover, our calculations are independent of the initial rotational quantum number.


2018 ◽  
Vol 96 (8) ◽  
pp. 926-932 ◽  
Author(s):  
Guan-Qing Ren ◽  
Ai-Ping Fu ◽  
Shu-Ping Yuan ◽  
Tian-Shu Chu

To investigate the dynamics mechanism of the Br + HgBr → Br2 + Hg reaction, the quasi-classical trajectory calculations are performed on Balabanov’s potential energy surface (PES) of ground electronic state. Both the scalar and vector properties are investigated to recognize the dynamics of the title reaction. Reaction probability for the total angular momentum quantum number J = 0 is determined at the collision energies (denoted as Ec) in a range of 1–25 kcal/mol, and the product vibrational distributions are given and compared between Ec = 20 and 40 kcal/mol. Other calculation values characterizing product polarizations including polarization-dependent differential cross sections (PDDCSs), distributions of P(θr), P([Formula: see text]), and P(θr, [Formula: see text]), are all discussed and compared between the two different collision energies in detail to analyze the alignment and orientation characteristics. It is revealed that the products prefer forward scattering and the PDDCSs are anisotropic in the whole range of the scattering angle. The product rotational angular momentum j′ shows a tendency to align perpendicular to the reagent relative velocity k. In fact, the product polarization of the title reaction is weak at both collision energies. In terms of horizontal comparison, the alignment is slightly stronger but the orientation is even less remarkable at higher collision energy.


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