The UK molecular R-matrix codes

Morgan, L A; Tennyson, Jonathan; Gillan, Charles J.

doi:10.1016/s0010-4655(98)00056-3

Cited by 183 publications

(161 citation statements)

References 24 publications

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“…The R-matrix method [6] splits configuration space into an inner region, which is a sphere of radius "a" about the target centre of mass, and an outer region (Figure 1). In this work values for "a" were tested in the range 10 -19 a 0 , with the results for LiH presented below being for the largest value.…”

Section: Theoretical Methodsmentioning

confidence: 99%

“…The target properties are obtained for LiH using the basis set from Salvini et al [8] and used the Slater-type orbital (STO) basis set of Cade and Huo [9]. For other systems the basis set employed were 6-311G* for CaF and DZP [6] for both H 2 S and HCN. The target properties like ground state energy, dipole moment and excitation energies were found to be in good agreement with previous results.…”

Section: Calculationmentioning

confidence: 99%

“…The target properties like ground state energy, dipole moment and excitation energies were found to be in good agreement with previous results. Scattering calculations were performed using the UK molecular R-matrix program suite [6]. The outer region calculation provides the interface between the inner and outer regions.…”

Section: Calculationmentioning

confidence: 99%

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Computation of Electron Impact Cross Sections from Molecules of Astrophysical Importance

Antony¹

2011

JMP

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Computations were performed for calculating cross sections of electron impact scattering from astrophysical targets CaF, HCN and H 2 S at energies lower than their ionization potential. The results show that the use of highly accurate R-matrix method which includes all the relevant physics and chemistry of the molecule in its formalism generate features significantly different from the simple static exchange calculation. The data obtained shows interesting structures in the eigen-phase sums which may be attributed to the dissociation channel of the molecule.

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Section: Theoretical Methodsmentioning

confidence: 99%

Section: Calculationmentioning

confidence: 99%

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Computation of Electron Impact Cross Sections from Molecules of Astrophysical Importance

Antony¹

2011

JMP

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“…Another popular method is based on the R-matrix theory (see, e.g., [27] and references therein), which has been implemented on different L 2 bases, including Gaussian functions [28][29][30][31][32][33][34][35][36][37]. While the R-matrix method offers, in principle, considerable flexibility, it also requires the evaluation of truncated electronic integrals, which are not implemented by default in standard quantum-chemistry codes.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Gaussian–B-spline basis for the electronic continuum: Photoionization of atomic hydrogen

2014

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As a first step towards meeting the recent demand for new computational tools capable of reproducing molecular-ionization continua in a wide energy range, we introduce a hybrid Gaussian-B-spline basis (GABS) that combines short-range Gaussian functions, compatible with standard quantum-chemistry computational codes, with B splines, a basis appropriate to represent electronic continua. We illustrate the performance of the GABS hybrid basis for the hydrogen atom by solving both the time-independent and the time-dependent Schrödinger equation for a few representative cases. The results are in excellent agreement with those obtained with a purely B-spline basis, with analytical results, when available, and with recent above-threshold ionization spectra from the literature. In the latter case, we report fully differential photoelectron distributions which offer further insight into the process of above-threshold ionization at different wavelengths.

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“…For example, the total cross sections for ionization of molecules by electron impact is one of the essential processes required in the modeling of a wide range of applications, such as plasma processing of semiconductor devices as it defines the number of charged particle balance and sustaining conditions for plasma operation. The importance of electron-molecule collisions has long been recognized and considerable progress in providing experimental data for electron-impact ionization cross sections for a broad range of molecular targets has been achieved in the past decade [11,12]. Nevertheless, the information on collision data and particularly complete sets of data for most reactive gases used in plasma processing are not available.…”

Section: Introductionmentioning

confidence: 99%

Calculations of Cross Sections Data for Scattering of Electrons on HBr

Radmilović-Radjenović

Petrović

2010

Acta Phys. Pol. A

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The R-matrix method provides a complete theoretical framework for the treatment of low energy electron collisions. The method has been implemented into code Quantemol-N (EE) with a goal to provide users in plasma modeling, swarm studies and other applications with an option to calculate the missing data. In this paper we report on cross sections and rate coefficients for hydrogen bromide obtained by using Quantemol-N. The total cross section has been calculated both with and without Born corrections.PACS numbers: 34.50.−s, 34.50.Gb IntroductionCollisions of electrons with atoms and molecules determine the behavior of plasmas. The electron impact ionization of a molecule represents a basic electron-molecule collision process important in many practical applications such as low-temperature processing plasmas [1-3], fusion-edge plasmas [4,5], gas discharges [6,7], radiation chemistry [8], mass spectrometry [9] and chemical analysis [10]. For example, the total cross sections for ionization of molecules by electron impact is one of the essential processes required in the modeling of a wide range of applications, such as plasma processing of semiconductor devices as it defines the number of charged particle balance and sustaining conditions for plasma operation. The importance of electron-molecule collisions has long been recognized and considerable progress in providing experimental data for electron-impact ionization cross sections for a broad range of molecular targets has been achieved in the past decade [11,12]. Nevertheless, the information on collision data and particularly complete sets of data for most reactive gases used in plasma processing are not available.Defining low energies as those when projectile electrons have an insufficient energy to ionize the target molecule, the following processes can occur: elastic scattering, electronic excitation, vibrational and rotational excitations, dissociative attachment/recombination and impact dissociation. A common feature of these processes is that they can be considered to proceed via a common intermediary [13]. The R-matrix method for treating electron--molecule collisions, used in this article, is designed to obtain accurate wavefunctions for this intermediary and can be used for the modeling the relevant processes. Although the loss of symmetry and increased degrees of freedom mean that electron-molecule collisions are significantly more difficult to treat theoretically than electron--atom collisions, the use of the R-matrix method to study

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The UK molecular R-matrix codes

Cited by 183 publications

References 24 publications

Computation of Electron Impact Cross Sections from Molecules of Astrophysical Importance

Computation of Electron Impact Cross Sections from Molecules of Astrophysical Importance

Hybrid Gaussian–B-spline basis for the electronic continuum: Photoionization of atomic hydrogen

Calculations of Cross Sections Data for Scattering of Electrons on HBr

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