scholarly journals NIFS Atomic and Molecular Numerical Database for Collision Processes

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 71 ◽  
Author(s):  
Izumi Murakami ◽  
Masatoshi Kato ◽  
Masahiko Emoto ◽  
Daiji Kato ◽  
Hiroyuki A. Sakaue ◽  
...  
Keyword(s):  
Cross Sections ◽  
Numerical Data ◽  
Data Sources ◽  
Rate Coefficients ◽  
Electron Collision ◽  
Fusion Plasma ◽  
Scattering Coefficients ◽  
Bibliographic Information ◽  
Ion Collisions ◽  
Collision Processes

The National Institute for Fusion Science (NIFS) has compiled and developed atomic and molecular numerical databases for various collision processes and makes it accessible from the internet to the public. The database contains numerical data of cross sections and rate coefficients for electron collision or ion collisions with atoms and molecules, attached with bibliographic information on their data sources. The database system provides query forms to search data, and numerical data are retrievable. The graphical output is helpful to understand energy dependence of cross sections and temperature dependence of rate coefficients obtained by various studies. All data are compiled mainly from published literature, and data sources can be tracked by the bibliographic information. We also have data of sputtering yields and back-scattering coefficients for solid surfaces collided by ions in the database. All data in the database are applicable to understand atomic and molecular processes in various plasmas, such as fusion plasma, astrophysical plasma and applied plasma, as well as for understanding plasma–surface interaction in plasmas.

scholarly journals Rotational and Vibrational Transitions in Molecular Collisions

1982 ◽  
Vol 35 (5) ◽  
pp. 593 ◽  
Author(s):  
J Peter Toennies
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Vibrational Excitation ◽  
Single Mode ◽  
Quantitative Agreement ◽  
Model Potential ◽  
Ion Collisions ◽  
Forced Oscillator ◽  
Mode Excitation ◽  
Collision Processes

Recent progress in understanding collision processes involving rotational and vibrational excitation in collisions of atoms (ions) with molecules in terms of simple models is illustrated for two systems. Rotational excitation of N2 in collision with He at 27 meV can be explained by an optical model. A more quantitative agreement is achieved by cross sections calculated exactly for the model potential of Tang and Toennies. Vibrational excitation probabilities for resolved single mode excitation of CF4 in small angle 10 eV ion collisions follow a Poisson distribution indicating a breathing sphere forced oscillator behaviour

scholarly journals Electron-Collision-Induced Dissociative Ionization Cross Sections for Silane

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Satyendra Pal ◽  
Neeraj Kumar ◽  
Anshu
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Theoretical Data ◽  
Ionization Rate ◽  
Dissociative Ionization ◽  
Rate Coefficients ◽  
Electron Collision ◽  
Differential Cross Sections ◽  
Ionization Cross ◽  
Ionization Cross Sections

Secondary electron energy and angle dependent differential cross sections for the production of cations SiHn+ (n=0–3), H2+ and H+ resulting from dissociative ionization of SiH4by electron collision have been evaluated at fixed incident electron energies of 100 and 200 eV. The semiempirical formulation of Jain and Khare which requires the oscillator strength data as a major input has been employed. In the absence of experimental data for differential cross sections, the corresponding derived integral partial and total ionization cross sections in the energy range varying from ionization threshold to 1000 eV revealed a satisfactory agreement with the available experimental and theoretical data. We have also evaluated the ionization rate coefficients on the basis of calculated partial ionization cross sections and Maxwell-Boltzmann energy distributions.

scholarly journals Improvement of the NIFS Atom and Molecular Database

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 91 ◽  
Author(s):  
Masahiko Emoto ◽  
Izumi Murakami ◽  
Daiji Kato ◽  
Masanobu Yoshida ◽  
Masatoshi Kato ◽  
...  
Keyword(s):  
Open Source ◽  
Cross Sections ◽  
Heavy Particle ◽  
Molecular Data ◽  
Rate Coefficients ◽  
Particle Collision ◽  
Online Databases ◽  
Collision Processes ◽  
Sputtering Yields ◽  
Ruby On Rails

The NIFS (National Institute for Fusion Science) Atom and Molecular Database, which has been available online since 1997, is a numerical atomic and molecular database of collision processes that is important for fusion research. This database provides the following: (1) the cross-sections and rate coefficients for ionization, excitation, and recombination caused by electron impact; (2) the charge transfer caused by heavy particle collision and collision processes of molecules; and (3) the sputtering yields of solids and backscattering coefficients from solids. It also offers a bibliographic database. We recently reconstructed the database system. The main purpose of the reconstruction was to migrate the database into an open-source architecture to make the system more flexible and extensible. The previous system used proprietary software and was difficult to customize. The new system consists of open-source software, including PostgreSQL database and Ruby on Rails. New features were also added to the system. The most important improvement is the interface with the Virtual Atomic and Molecular Data Center (VAMDC) portal. Using this interface, researchers can search for data in the NIFS database as well as in various other online databases simultaneously.

Electron collision cross sections and rate coefficients for the Na-like Cu ion

1996 ◽  
Vol 36 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Ying Zhang ◽  
Qiren Zhu ◽  
Shoufu Pan ◽  
Guizhen Shi
Keyword(s):  
Cross Sections ◽  
Rate Coefficients ◽  
Electron Collision ◽  
Collision Cross Sections

Collision Processes Involving Highly Ionized Atoms

1951 ◽  
Vol 4 (4) ◽  
pp. 437
Author(s):  
ER Hill
Keyword(s):  
Quantum Theory ◽  
Cross Section ◽  
Cross Sections ◽  
Radiative Recombination ◽  
Inelastic Collisions ◽  
Electron Collision ◽  
Mechanical Methods ◽  
Classical Quantum ◽  
Collision Processes ◽  
The Cross

The cross section of FeXIV for inelastic collisions resulting in the transition from the 2P3/2 to the 2P1/2 state of the ion, for electron collision ionization, and for radiative recombination of FeXIV and MgX are calculated by wave mechanical methods. A method is given whereby radiative recombination cross sections of all highly ionized atoms may be calculated. Where possible the cross sections obtained are compared with corresponding results given by the classical quantum theory. Finally, the wave mechanical values are used to verify the general conclusion, obtained using classical quantum values of the cross sections, that the agitation temperature of the coronal electrons is about 106 �K.

Rotational de-excitations of C3H+ (1Σ+) by collision with He: new ab initio potential energy surface and scattering calculations

2020 ◽  
Vol 494 (4) ◽  
pp. 5675-5681 ◽  
Author(s):  
Sanchit Chhabra ◽  
T J Dhilip Kumar
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Ab Initio ◽  
Cross Sections ◽  
Energy Surface ◽  
Molecular Ions ◽  
Basis Set ◽  
Rate Coefficients ◽  
Close Coupling ◽  
Collisional Rate Coefficients

ABSTRACT Molecular ions play an important role in the astrochemistry of interstellar and circumstellar media. C3H+ has been identified in the interstellar medium recently. A new potential energy surface of the C3H+–He van der Waals complex is computed using the ab initio explicitly correlated coupled cluster with the single, double and perturbative triple excitation [CCSD(T)-F12] method and the augmented correlation consistent polarized valence triple zeta (aug-cc-pVTZ) basis set. The potential presents a well of 174.6 cm−1 in linear geometry towards the H end. Calculations of pure rotational excitation cross-sections of C3H+ by He are carried out using the exact quantum mechanical close-coupling approach. Cross-sections for transitions among the rotational levels of C3H+ are computed for energies up to 600 cm−1. The cross-sections are used to obtain the collisional rate coefficients for temperatures T ≤ 100 K. Along with laboratory experiments, the results obtained in this work may be very useful for astrophysical applications to understand hydrocarbon chemistry.

scholarly journals Calculation of Electron Impact Single Ionization TDCS of Tungsten Atoms at 200, 500 and 1000 eV

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 31
Author(s):  
Ghanshyam Purohit
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Projectile Energy ◽  
Cross Section Data ◽  
Scattered Electron ◽  
Fusion Plasma ◽  
Magnetic Devices ◽  
Single Ionization ◽  
Section Data ◽  
Sensitive Dependence

We report triple differential cross-sections (TDCSs) for the electron impact single ionization of tungsten atoms for the ionization taking place from the outer sub shells of tungsten atoms, viz. W (6s), W (5d), W (5p) and W (4f). The study of the electron-induced processes such as ionization, excitation, autoionization from tungsten and its charged states is strongly required to diagnose and model the fusion plasma in magnetic devices such as Tokamaks. Particularly, the cross-section data are important to understand the electron spectroscopy involved in the fusion plasma. In the present study, we report TDCS results for the ionization of W atoms at 200, 500 and 1000 eV projectile energy at different values of scattered electron angles. It was observed that the trends of TDCSs for W (5d) are significantly different from the trends of TDCSs for W (6s), W (5p) and W (4f). It was further observed that the TDCS for W atoms has sensitive dependence on value of momentum transfer and projectile energy.

CHARMONIUM PRODUCTION IN Pb–Pb COLLISIONS AT ALICE: FROM SUPPRESSION TO REGENERATION?

2013 ◽  
Vol 28 (21) ◽  
pp. 1330018 ◽  
Author(s):  
ENRICO SCOMPARIN
Keyword(s):  
Phase Transition ◽  
Cross Sections ◽  
Short Review ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Alice Experiment ◽  
Model Calculations ◽  
Ion Collisions ◽  
Quark Production ◽  
History Of

Heavy quarkonium states are considered as one of the key observables for the study of the phase transition from a system made of hadrons towards a Quark–Gluon Plasma (QGP). In the last 25 years, experiments at CERN and Brookhaven have studied collisions of heavy ions looking for a suppression of charmonia/bottomonia, considered as a signature of the phase transition. After an introduction to the main concepts behind these studies and a short review of the SPS and RHIC results, I will describe the results obtained in Pb – Pb collisions by the ALICE experiment at the LHC. The ALICE findings will be critically compared to those of lower energy experiments, to CMS results, and to model calculations. The large cross-sections for heavy-quark production at LHC energies are expected to induce a novel production mechanism for charmonia in heavy-ion collisions, related to a recombination of [Formula: see text] pairs along the history of the collision and/or at hadronization. The occurrence of such a process at the LHC will be discussed. Finally, prospects for future measurements will be shortly addressed.

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