Extremely short-lived reaction resonances in Cl + HD (v = 1) → DCl + H due to chemical bond softening

Science ◽  
2015 ◽  
Vol 347 (6217) ◽  
pp. 60-63 ◽  
Author(s):  
Tiangang Yang ◽  
Jun Chen ◽  
Long Huang ◽  
Tao Wang ◽  
Chunlei Xiao ◽  
...  
Keyword(s):  
Chemical Bond ◽  
Quantum Number ◽  
Quantum Dynamics ◽  
Rotational Quantum Number ◽  
Vibrationally Excited ◽  
Potential Wells ◽  
Chemical Reaction Dynamics ◽  
Benchmark System ◽  
Bond Softening ◽  
Direct Abstraction

The Cl + H2 reaction is an important benchmark system in the study of chemical reaction dynamics that has always appeared to proceed via a direct abstraction mechanism, with no clear signature of reaction resonances. Here we report a high-resolution crossed–molecular beam study on the Cl + HD (v = 1, j = 0) → DCl + H reaction (where v is the vibrational quantum number and j is the rotational quantum number). Very few forward scattered products were observed. However, two distinctive peaks at collision energies of 2.4 and 4.3 kilocalories per mole for the DCl (v′ = 1) product were detected in the backward scattering direction. Detailed quantum dynamics calculations on a highly accurate potential energy surface suggested that these features originate from two very short-lived dynamical resonances trapped in the peculiar H-DCl (v′ = 2) vibrational adiabatic potential wells that result from chemical bond softening. We anticipate that dynamical resonances trapped in such wells exist in many reactions involving vibrationally excited molecules.

Quantum interference in H + HD → H2 + D between direct abstraction and roaming insertion pathways

Science ◽  
2020 ◽  
Vol 368 (6492) ◽  
pp. 767-771 ◽  
Author(s):  
Yurun Xie ◽  
Hailin Zhao ◽  
Yufeng Wang ◽  
Yin Huang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Quantum Number ◽  
Quantum Interference ◽  
Chemical Reactivity ◽  
Rotational Quantum Number ◽  
Interesting Case ◽  
Phase Effect ◽  
Chemical Reaction Dynamics ◽  
Bohm Effect ◽  
Aharonov Bohm ◽  
Direct Abstraction

Understanding quantum interferences is essential to the study of chemical reaction dynamics. Here, we provide an interesting case of quantum interference between two topologically distinct pathways in the H + HD → H2 + D reaction in the collision energy range between 1.94 and 2.21 eV, manifested as oscillations in the energy dependence of the differential cross section for the H2 (v′ = 2, j′ = 3) product (where v′ is the vibrational quantum number and j′ is the rotational quantum number) in the backward scattering direction. The notable oscillation patterns observed are attributed to the strong quantum interference between the direct abstraction pathway and an unusual roaming insertion pathway. More interestingly, the observed interference pattern also provides a sensitive probe of the geometric phase effect at an energy far below the conical intersection in this reaction, which resembles the Aharonov–Bohm effect in physics, clearly demonstrating the quantum nature of chemical reactivity.

Molecules in strong laser fields: vibrational inversion and harmonic generation

1994 ◽  
Vol 72 (3) ◽  
pp. 673-677 ◽  
Author(s):  
Eric E. Aubanel ◽  
André D. Bandrauk
Keyword(s):  
Harmonic Generation ◽  
Laser Pulses ◽  
Harmonic Spectrum ◽  
Femtosecond Laser Pulses ◽  
Generation Process ◽  
High Order Harmonic Generation ◽  
Vibrationally Excited ◽  
Potential Wells ◽  
High Order Harmonic ◽  
Vibrational Levels

We examine two consequences of the unique behaviour of molecules in strong fields. First, by time gating of laser-induced avoided crossings with femtosecond laser pulses, one can obtain efficient vibrational inversion into a narrow distribution of vibrational levels of a molecular ion. We demonstrate this by numerical solution of the time-dependent Schrödinger equation for [Formula: see text] Second, we show results of numerical calculation with vibrationally excited [Formula: see text] of harmonic generation up to the 11th order of an intense 1064- nm laser. We predict that competition of photodissociation can be minimized by trapping the molecule in high-field-induced potential wells, thus enhancing the high-order harmonic generation process. Furthermore, the harmonic spectrum can serve as a measure of the structure of these laser-induced potentials.

A quasi-classical trajectory study of the reagent initial rotation quantum state effect on the reaction He + T2+ → HeT+ + T using an improved ab initio potential energy surface

2012 ◽  
Vol 90 (2) ◽  
pp. 230-236 ◽  
Author(s):  
Ningjiu Zhao ◽  
Yufang Liu
Keyword(s):  
Angular Momentum ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum Number ◽  
Relative Velocity ◽  
Energy Surface ◽  
Rotational Quantum Number ◽  
Chem Phys ◽  
Classical Trajectory ◽  
Positive Direction

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.

scholarly journals Measurements of The Spectroscopic Properties of Hydrogen Iodide Molecules

2008 ◽  
Vol 5 (3) ◽  
pp. 446-448
Author(s):  
Baghdad Science Journal
Keyword(s):  
Absorption Spectrum ◽  
Quantum Number ◽  
Rotational Quantum Number ◽  
Spectroscopic Properties ◽  
Hydrogen Iodide

A calculation have been carried out for determination some of the spectroscopic properties of Hydrogen Iodide HI molecules such as, the intensity of the absorption spectrum as a function of the variation of the temperature ranging from 10 to 1000 K. This study shows that the populations and hence intensity of the molecule increased as the temperature increased. Another determination of the maximum rotational quantum number Jmax of N2 , CO , BrF AgCl and HI molecules has been carried out.

scholarly journals Rotation Effect in Morse Potential For K2 Molecule

2011 ◽  
Vol 8 (4) ◽  
pp. 968-971
Author(s):  
Baghdad Science Journal
Keyword(s):  
Quantum Number ◽  
Dissociation Energy ◽  
Effective Potential ◽  
Morse Potential ◽  
Rotational Quantum Number ◽  
Electronic States ◽  
Rotation Effect ◽  
Potential Curves

The rotation effect upon Morse potential had been studied and the values of the effective potential in potential curves had been calculated for electronic states (X2?+g , B ?u ) K2 molecule. The calculation had been computed for rotational quantum number (J = 5). Also, drawing potential curves for these systems had been done using Herzberg and Gaydon equations. It was found that the values of the dissociation energy which resulting from using Herzberg equation greater than that of Gaydon equation. Besides, it was found that the rotation effect for (X and B) electronic states in Morse potential is very small and in this case may negligible.

scholarly journals Symmetry selected quantum dynamics of few electrons in nanopillar transistors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yue-Min Wan ◽  
Heng-Tien Lin
Keyword(s):  
Quantum Number ◽  
Quantum Dynamics ◽  
Three Dimensional ◽  
Single Electron ◽  
Electron Hole ◽  
Current Voltage ◽  
Weak Symmetry ◽  
Current Voltage Characteristics ◽  
The One

AbstractStudy on single electron tunnel using current-voltage characteristics in nanopillar transistors at 298 K show that the mapping between the Nth electron excited in the central box ∼8.5 × 8.5 × 3 nm3 and the Nth tunnel peak is not in the one-to-one correspondence to suggest that the total number N of electrons is not the best quantum number for characterizing the quality of single electron tunnel in a three-dimensional quantum box transistor. Instead, we find that the best number is the sub-quantum number nz of the conduction z channel. When the number of electrons in nz is charged to be even and the number of electrons excited in the nx and ny are also even at two, the adding of the third electron into the easy nx/ny channels creates a weak symmetry breaking in the parity conserved x-y plane to assist the indirect tunnel of electrons. A comprehensive model that incorporates the interactions of electron-electron, spin-spin, electron-phonon, and electron-hole is proposed to explain how the excited even electrons can be stabilized in the electric-field driving channel. Quantum selection rules with hierarchy for the ni (i = x, y, z) and N = Σni are tabulated to prove the superiority of nz over N.

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