scholarly journals Reaction cross sections and thermal rate constant for Cl− + CH3Br → ClCH3 + Br− from J-dependent quantum scattering calculations

2016 ◽  
Vol 18 (29) ◽  
pp. 19668-19675 ◽  
Author(s):  
Carsten Hennig ◽  
Stefan Schmatz
Keyword(s):  
Gas Phase ◽  
Cross Sections ◽  
Scattering Theory ◽  
Total Angular Momentum ◽  
Reaction Cross ◽  
Quantum Scattering ◽  
Initial State ◽  
Quantum Scattering Theory ◽  
Reduced Time ◽  
Reaction Cross Sections

Employing dimensionality-reduced time-independent quantum scattering theory and summation over all possible total angular momentum states, initial-state selected reaction cross sections for the exothermic gas-phase bimolecular nucleophilic substitution (SN2) reaction Cl− + CH3Br → ClCH3 + Br− have been calculated.

Ion-molecule reactions of methyl fluoride and methylene chloride

1970 ◽  
Vol 23 (11) ◽  
pp. 2301 ◽  
Author(s):  
NA McAskill
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Cross Sections ◽  
Main Product ◽  
Methylene Chloride ◽  
Reaction Cross ◽  
Rate Coefficients ◽  
Ion Molecule Reactions ◽  
Reaction Cross Sections

The ion-molecule reactions of CH3F and CH2Cl2 were examined in the gas phase using a high-pressure mass spectrometer. The ionic products of CH3F were mainly CH2F+, C2H6F+, and CH4F+. In the CH2Cl2 system the main product was CHCl2+ together with smaller amounts of CH2Cl+, CH3Cl2+, and several condensation ions. The ionic reactivity of the two compounds was compared to that of other halomethanes. Rate coefficients and reaction cross sections for many primary reactant ions were measured as a function of the ion exit energy.

scholarly journals Quantum and classical effects at scattering of high energy charged particles in thin crystals

2018 ◽  
pp. 5-11
Author(s):  
N.F. Shul'ga ◽  
S.N. Shulga
Keyword(s):  
Cross Sections ◽  
Scattering Theory ◽  
Scattering Amplitude ◽  
Operator Method ◽  
Eikonal Approximation ◽  
High Energy ◽  
Particle Energy ◽  
Quantum Scattering ◽  
Quantum Scattering Theory ◽  
Scattering Cross

The present work reviews the results concerning quantum scattering theory of ultrarelativistic electrons in ultrathin crystals and its comparison with analogous classical results. It deals with an intermediate range of thicknesses, large enough for that the particle motion could not be considered as rectilinear but small enough for that the channeling regime of motion was not established. The quantum theory is based both upon the representation of the scattering amplitude as an integral over the surface surrounding the target, and on the so-called operator method of determination of the wave function as a solution of a Schrödinger-like equation. The latter method implies a wide use of the Fourier technique, both in calculation of each next step in the wave packet evolution, and in moving from the spatial coordinates to the angular ones. The authors compare the quantum differential scattering cross-sections with the classical ones in the considered range of crystal thicknesses and show their resemblances, distinctions and the evolution of these distinctions with the change of the particle energy. The simplest variant of quantum scattering theory based upon the eikonal approximation of quantum mechanics is considered. In the paper the quantum differential scattering cross-section was calculated and its affinity with the classical one was demonstrated. In the preparation of these lecture notes the material of the paper [4] was used.

Formation of α clusters in dilute neutron-rich matter

Science ◽  
2021 ◽  
Vol 371 (6526) ◽  
pp. 260-264 ◽  
Author(s):  
Junki Tanaka ◽  
Zaihong Yang ◽  
Stefan Typel ◽  
Satoshi Adachi ◽  
Shiwei Bai ◽  
...  
Keyword(s):  
Cross Sections ◽  
Cluster Formation ◽  
Reaction Cross ◽  
Skin Thickness ◽  
Neutron Skin ◽  
Heavy Nuclei ◽  
Α Decay ◽  
Neutron Skin Thickness ◽  
Reaction Cross Sections ◽  
Α Particles

The surface of neutron-rich heavy nuclei, with a neutron skin created by excess neutrons, provides an important terrestrial model system to study dilute neutron-rich matter. By using quasi-free α cluster–knockout reactions, we obtained direct experimental evidence for the formation of α clusters at the surface of neutron-rich tin isotopes. The observed monotonous decrease of the reaction cross sections with increasing mass number, in excellent agreement with the theoretical prediction, implies a tight interplay between α-cluster formation and the neutron skin. This result, in turn, calls for a revision of the correlation between the neutron-skin thickness and the density dependence of the symmetry energy, which is essential for understanding neutron stars. Our result also provides a natural explanation for the origin of α particles in α decay.

scholarly journals 7Be and 8B reaction dynamics at Coulomb barrier energies

2018 ◽  
Vol 184 ◽  
pp. 02015
Author(s):  
E. Strano ◽  
M. Mazzocco ◽  
A. Boiano ◽  
C. Boiano ◽  
M. La Commara ◽  
...  
Keyword(s):  
Cross Sections ◽  
Coulomb Barrier ◽  
Reaction Cross Section ◽  
Optical Model ◽  
Reaction Dynamics ◽  
Reaction Cross ◽  
Total Reaction Cross Section ◽  
Weakly Bound ◽  
Total Reaction ◽  
Reaction Cross Sections

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

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