Rotational excitation in electron-molecule scattering at intermediate collision energy: A two-centre scattering model

1990 ◽  
Vol 15 (3) ◽  
pp. 227-237 ◽  
Author(s):  
H. J. Korsch ◽  
H. D. Meyer ◽  
C. P. Shukla
Keyword(s):  
Collision Energy ◽  
Rotational Excitation ◽  
Scattering Model ◽  
Molecule Scattering

Glauber amplitudes for rotational excitation ine−-molecule scattering via quadrupole potentials

1978 ◽  
Vol 18 (1) ◽  
pp. 74-81 ◽  
Author(s):  
N. K. Rahman ◽  
F. A. Gianturco ◽  
U. T. Lamanna
Keyword(s):  
Rotational Excitation ◽  
Molecule Scattering

Seemingly Anomalous Angular Distributions in H + D2 Reactive Scattering

Science ◽  
2012 ◽  
Vol 336 (6089) ◽  
pp. 1687-1690 ◽  
Author(s):  
Justin Jankunas ◽  
Richard N. Zare ◽  
Foudhil Bouakline ◽  
Stuart C. Althorpe ◽  
Diego Herráez-Aguilar ◽  
...  
Keyword(s):  
Cross Sections ◽  
Collision Energy ◽  
Minimum Energy ◽  
Angular Distributions ◽  
Quantum Mechanical ◽  
Minimum Energy Path ◽  
Reactive Scattering ◽  
Rotational Excitation ◽  
Reaction Products ◽  
Trajectory Calculations

When a hydrogen (H) atom approaches a deuterium (D2) molecule, the minimum-energy path is for the three nuclei to line up. Consequently, nearly collinear collisions cause HD reaction products to be backscattered with low rotational excitation, whereas more glancing collisions yield sideways-scattered HD products with higher rotational excitation. Here we report that measured cross sections for the H + D2 → HD(v′ = 4, j′) + D reaction at a collision energy of 1.97 electron volts contradict this behavior. The anomalous angular distributions match closely fully quantum mechanical calculations, and for the most part quasiclassical trajectory calculations. As the energy available in product recoil is reduced, a rotational barrier to reaction cuts off contributions from glancing collisions, causing high-j′ HD products to become backward scattered.

ROTATIONAL ALIGNMENT OF PRODUCT MOLECULES FROM THE REACTION Ca + HCl→CaCl + H

2011 ◽  
Vol 10 (01) ◽  
pp. 19-29 ◽  
Author(s):  
PING-YING TANG ◽  
DONG-LIN LI ◽  
MENG-MENG WU ◽  
BI-YU TANG
Keyword(s):  
Angular Distribution ◽  
Ab Initio ◽  
Collision Energy ◽  
Potential Surface ◽  
The State ◽  
Rotational Alignment ◽  
Angle Distribution ◽  
Rotational Excitation ◽  
Polar Plot ◽  
Trajectory Method

The product rotational polarization in the Ca + HCl→CaCl + H reaction at collision energy of 20 kcal/mol has been studied via the quasiclassical trajectory method on a new ab initio potential surface. The P(θ r ) distribution of angle between k and j′, and the dihedral angular distribution P(Φ r ) characterizing k - k′ - j′ correlation are discussed, the angle distribution P(θ r , Φ r ) of product rotational vectors in the form of polar plot in θ r and Φ r are shown. Furthermore, four PDDCSs (2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt) and (2π/σ)(dσ21-/dωt) are also presented. The present calculations reveal that the product rotational alignment is very strong. Finally, the state distributions of the product CaCl are investigated. The results showed that the CaCl product was formed with high vibrational and rotational excitation.

EFFECTS OF ROTATIONAL AND VIBRATIONAL EXCITATION ON THE STEREODYNAMICS OF THE O (D-1) + HCl → OH + Cl REACTION

2009 ◽  
Vol 08 (06) ◽  
pp. 1177-1184 ◽  
Author(s):  
QIANG WEI ◽  
VICTOR WEI-KEH WU ◽  
BO ZHOU
Keyword(s):  
Cross Sections ◽  
Collision Energy ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Rotational Excitation ◽  
Title Reaction ◽  
Vibrational Excitations ◽  
Product Vector ◽  
Good Agreement

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.

scholarly journals State-to-state rotational excitation of CO by H2 near 1000 cm−1 collision energy

2000 ◽  
Vol 112 (2) ◽  
pp. 554-559 ◽  
Author(s):  
Stiliana Antonova ◽  
Antonis P. Tsakotellis ◽  
Ao Lin ◽  
George C. McBane
Keyword(s):  
Collision Energy ◽  
Rotational Excitation

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
Keyword(s):  
Angular Momentum ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Collision Energy ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Rotational Excitation ◽  
Title Reaction ◽  
Trajectory Method

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.

Positron-molecule scattering at low and medium energies

1996 ◽  
Vol 74 (7-8) ◽  
pp. 420-425 ◽  
Author(s):  
A. S. Ghosh ◽  
T. Mukherjee
Keyword(s):  
Cross Sections ◽  
Laboratory Frame ◽  
Excitation Threshold ◽  
Rotational Excitation ◽  
Close Coupling ◽  
Intermediate Energies ◽  
Recent Developments ◽  
Molecule Scattering ◽  
Scattering Cross Sections ◽  
Threshold Energies

This review surveys the recent developments carried out by us on positron–molecule scattering at low and intermediate energies. The relative merits between the laboratory frame rotational close-coupling (rotational LFCC) and the adiabatic nuclei rotation models near the electronic and rotational excitation threshold energies are discussed. The importance of the use of the rotational LFCC model for polar molecules is also reviewed. The rovibrational LFCC and the adiabatic nuclei rovibration models are used to calculate the scattering cross sections for e+–H2 scattering. The results demonstrate the necessity of the inclusion of the vibrational motion dynamically in the theory.

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