Effect of Electrostatic Interactions on Effective Cross-Sections for Collision of Small Particles With Neutral Molecules

1993 ◽  
Vol 46 (1) ◽  
pp. 13 ◽  
Author(s):  
LF Phillips
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Atmospheric Aerosols ◽  
Electrostatic Interactions ◽  
Interstellar Dust ◽  
Effective Cross Section ◽  
Classical Trajectory ◽  
Polar Molecules ◽  
Interstellar Dust Grains ◽  
Geometrical Cross Section

Quasi-classical trajectory calculations have been used to calculate effective collision cross-sections for polar and non-polar molecules with charged and neutral conducting spheres of radius 0.001-0.1 μm over the temperature range 10-400 K. In general the effective cross-section is much larger than the geometrical cross-section, especially for small, highly charged, particles colliding with highly polar molecules at low temperatures. The results may have a bearing on the growth of atmospheric aerosols and of interstellar dust grains.

Computer simulation of (n, p) modifications in silicon nitride (Si3N4) nanoparticles

2020 ◽  
Vol 34 (32) ◽  
pp. 2050318
Author(s):  
T. G. Naghiyev
Keyword(s):  
Computer Simulation ◽  
Silicon Nitride ◽  
Stable Isotope ◽  
Cross Section ◽  
Cross Sections ◽  
Effective Cross Section

(n, p) transmutations in the silicon nitride (Si3N4) nanoparticles by the neutrons at different energies have been studied by computer simulation. The transmutations by neutrons in the nanomaterial were separately investigated for silicon and nitrogen atoms in the Si3N4 particles. Since the effective cross-section of the possible probability of transmutation is different in the various types of silicon and nitrogen atoms, the modeling was performed separately for each stable isotope. The spectra of the effective cross-sections of the (n, p) transmutations for silicon and nitrogen atoms have been studied in relation to each other.

QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION PROBABILITY AND CROSS SECTION OF THE REACTION LiH + H

2013 ◽  
Vol 12 (01) ◽  
pp. 1250093 ◽  
Author(s):  
YULIANG WANG ◽  
JINCHUN ZHANG ◽  
BAOGUO TIAN ◽  
KUN WANG ◽  
XIAORUI LIANG ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Collision Energy ◽  
Energy Surface ◽  
Classical Trajectory ◽  
Reaction Cross ◽  
Reaction Probability ◽  
Title Reaction ◽  
Reaction Cross Sections

Based on the new accurate potential energy surface of the ground state of LiH2 system. Quasi-classical trajectory (QCT) calculations were carried out for the reaction LiH + H . The reaction probability of the title reaction for J = 0 has been calculated. The reaction cross sections were calculated as functions of the collision energy in the range 0.1–2.5 eV. The results were found to be well consistent with the previous real wave packet (RWP) and QCT results.

EXCITATION CURVES FOR THE REACTIONS Fe56(n, p)Mn56 AND Co59(n, α)Mn56

1964 ◽  
Vol 42 (6) ◽  
pp. 1030-1036 ◽  
Author(s):  
D. C. Santry ◽  
J. P. Butler
Keyword(s):  
Cross Section ◽  
Neutron Spectrum ◽  
Neutron Energy ◽  
Cross Sections ◽  
Effective Cross Section ◽  
Fission Neutron ◽  
Reaction Cross ◽  
Fission Neutron Spectrum ◽  
Threshold Energies ◽  
Reaction Cross Sections

Excitation curves for the reactions Fe56(n, p)Mn56 and Co59(n, α)Mn56 have been measured by the activation method from near threshold energies to 20.3 Mev. The measurements are relative to the known cross section for the S32(n, p)P32 reaction. Cross sections for both reactions increase smoothly with neutron energy and reach maximum values of 119 ± 4 mb for the Fe56(n, p) reaction at 13.6 Mev and 30.0 ± 0.9 mb for the Co59(n, α) reaction at 14.5 Mev. Above 15 Mev both cross sections decrease with neutron energy. From the excitation curves effective cross-section values for a fission-neutron spectrum have been calculated as 1.04 ± 0.05 mb for the (n, p) reaction and 0.140 ± 0.007 mb for the (n, α) reaction.

Cross Section Measurements for the 103Rh(n,n′)103Rhm Reaction from 0.122 to 14.74 MeV

1974 ◽  
Vol 52 (15) ◽  
pp. 1421-1428 ◽  
Author(s):  
D. C. Santry ◽  
J. P. Butler
Keyword(s):  
Neutron Flux ◽  
Cross Section ◽  
Neutron Spectrum ◽  
Cross Sections ◽  
Energy Levels ◽  
Effective Cross Section ◽  
Fission Neutron ◽  
Activation Method ◽  
Excitation Curve ◽  
Fission Neutron Spectrum

Cross sections for the production of 103Rhm were measured by the activation method. At energies below 5.3 MeV the neutron flux was measured with a calibrated neutron long counter, while at higher energies, measurements were made relative to the known cross section for the 32S(n,p)32P reaction. The shape of the Rh excitation curve is discussed in terms of known energy levels in 103Rh. An effective cross section for a 235U fission neutron spectrum calculated from the measured excitation curve is 724 ± 43 mb.

scholarly journals DPS mechanism for associated $$c\bar{c} b\bar{b}$$ production in AA UPCs

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Edgar Huayra ◽  
Emmanuel G. de Oliveira ◽  
Roman Pasechnik
Keyword(s):  
Production Process ◽  
Cross Section ◽  
Photon Energy ◽  
Cross Sections ◽  
Effective Cross Section ◽  
Double Parton Scattering ◽  
Quark Pairs ◽  
Numerical Predictions ◽  
Energy Dependent ◽  
Parton Scattering

Abstract We discuss the associated $$c\bar{c}$$cc¯ and $$b\bar{b}$$bb¯ quark pairs production in the double-parton scattering (DPS) process in ultraperipheral (UPCs) AA collisions. We derive an analogue of the inclusive DPS pocket formula and the photon-energy dependent effective cross section considering an overlap between the hard SPS scatterings. We provide numerical predictions for the DPS cross sections for the $$c\bar{c}b\bar{b}$$cc¯bb¯ production process at the typical energies of AA UPCs at the LHC and FCC colliders and also characterize the A dependence of the total UPC DPS cross section.

EXCITATION CURVES FOR THE REACTIONS Al27(n, α)Na24 AND Mg24(n, p)Na24

1963 ◽  
Vol 41 (2) ◽  
pp. 372-383 ◽  
Author(s):  
J. P. Butler ◽  
D. C. Santry
Keyword(s):  
Cross Section ◽  
Neutron Spectrum ◽  
Cross Sections ◽  
Effective Cross Section ◽  
Fission Neutron ◽  
Activation Method ◽  
Graaff Accelerator ◽  
Fission Neutron Spectrum ◽  
Van De Graaff ◽  
Threshold Energies

Excitation curves for the reactions Al27(n, α)Na24 and Mg24(n, p)Na24 have been measured by the activation method from near threshold energies to 20.3 Mev. The measurements are relative to the known cross section for the reaction S32(n, p)P32. Monoenergetic neutrons were obtained from the D(d, n)He3, T(d, n)He4, and the T(p, n)He3 reactions employing a Tandem Van de Graaff accelerator or 125-kev accelerator. Cross sections for both reactions rise above the minimum detectable value of 0.02 mb near 5 Mev and reach maximum values of 126 mb for the Al(n, α)Na24 reaction and 205 mb for the Mg24(n, p)Na24 reaction at 13.5 Mev. Above this energy both cross sections decrease. From the excitation curves effective cross-section values for a fission-neutron spectrum have been calculated as 0.61 ± 0.03 mb for the (n, α) reaction and 1.34 ± 0.07 mb for the (n, p) reaction.

Cross sections for the 93Nb(n,2n)92mNb reaction

1990 ◽  
Vol 68 (7-8) ◽  
pp. 582-586 ◽  
Author(s):  
D. C. Santry ◽  
R. D. Werner
Keyword(s):  
Cross Section ◽  
Neutron Spectrum ◽  
Cross Sections ◽  
Threshold Energy ◽  
Effective Cross Section ◽  
Fission Neutron ◽  
Transfer Standard ◽  
Fission Neutron Spectrum ◽  
Maximum Value ◽  
The Cross

The cross section of the 93Nb(n,2n)92mNb reaction has been studied by use of the activation method from the threshold energy of 8.8–19.8 MeV. Measurements are relative to the known cross-section values for the reactions H(n,n)H, 32S(n,p)32p, and 27Al(n,α)24Na. The cross-section value increases smoothly with energy and reaches a maximum value of 444 ± 18 mb at about 14.5 MeV then decreases to values of 293 ± 14 mb at 19.8 MeV. An effective cross-section value for a fission neutron spectrum calculated from the results is 0.321 ± 0.019 mb. The activation of Nb as a transfer standard for 14 MeV neutrons is discussed.

MEASUREMENT OF RADIATIVE CAPTURE RESONANCE INTEGRALS IN A THERMAL REACTOR SPECTRUM, AND THE THERMAL CROSS SECTION OF Pu-240

1960 ◽  
Vol 38 (1) ◽  
pp. 57-77 ◽  
Author(s):  
W. H. Walker ◽  
C. H. Westcott ◽  
T. K. Alexander
Keyword(s):  
Cross Section ◽  
Neutron Beam ◽  
Cross Sections ◽  
Radiative Capture ◽  
Effective Cross Section ◽  
Mean Value ◽  
Resonance Integral ◽  
Thermal Reactor ◽  
Thermal Cross Section ◽  
Radiative Neutron Capture

An apparatus is described which detects γ-rays emitted by a thin target placed in a well-denned neutron beam. It has been used to determine the Cd ratios of Au and Pu-240, from which the ratio of the resonance integral to the 2200 m/s cross section for radiative neutron capture in Pu-240 has been deduced, using Au as a reference standard. Using this ratio and previously measured values of the resonance integral of Pu-240 and its effective cross section in two positions in the NRX reactor, three separate estimates of the 2200 m/s cross section of Pu-240 have been made. The mean value is 270 ± 17 barns.In an auxiliary experiment to indicate the shape of the epithermal spectrum of the neutron beam, the activation Cd ratios of Mn and In were compared with that of Au. These results, combined with the known 2200 m/s capture cross sections of these nuclides, yield new values of the radiative capture resonance integrals for both Mn and In.

QUASI-CLASSICAL TRAJECTORY STUDY OF THE REACTION N + NH (v = 0–3, j=0) → N2 + H

2013 ◽  
Vol 12 (03) ◽  
pp. 1350015 ◽  
Author(s):  
ZHENYU XU ◽  
YUNHUI WANG ◽  
RUIFENG LU
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Collision Energy ◽  
Energy Surface ◽  
Vibrational Excitation ◽  
Classical Trajectory ◽  
Reaction Probability ◽  
Many Body ◽  
Generalized Polarization

The quasi-classical trajectory (QCT) calculations have been carried out for the reaction N + NH (v = 0–3, j=0) → N2 + H on the ground state of double many-body expansion (DMBE) potential energy surface [Caridade, PJSB, Poveda LA, Rodrigues SPJ, Varandas AJC, J Phys Chem A111:1172, 2007]. The influence of reagent vibrational excitation on reaction probability for total angular momentum J = 0 and integral cross section (ICS) at collision energies ranging from 0.1 eV to 1.0 eV has been investigated. The reaction probability tends to decrease with increasing collision energy and increase with the rising of initial vibration state, although some fluctuations appear. The ICS declines monotonously with the increase of collision energy and v. The product rotational alignment factor 〈P2(j′•k)〉 has also been calculated, and its value has a declining trend with the increase of collision energy. In spite of that, the results still show that the product is highly aligned. In addition, the vibrational excitation effect on the product polarization has also been studied. All the distributions of P(ϕr), P(θr), and the generalized polarization dependent differential cross sections indicate dependent behaviors on v.

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