A configuration interaction program

Fischer, Charlotte Froese

doi:10.1016/0010-4655(91)90139-c

Cited by 64 publications

(48 citation statements)

References 10 publications

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“…In the second step one calculates the electron correlation energy in terms of the orbitals from the first step, in particular by considering excitations (or de‐excitations) of one, two, three, or more electrons from occupied orbitals in the reference function to various unoccupied orbitals. A key issue in such calculations is whether the reference function consists of a single configuration state function129, 131–133 (CSF) or a linear combination of two or more CSFs,13, 43, 84, 91, 120, 129, 134–140 where a CSF is an antisymmetric many‐electron trial wave function composed (usually) of the minimum number of Slater determinants required to obtain the correct spatial and spin symmetry. Calculations in which the reference functions are single CSFs (such as Hartree–Fock wave functions) are called single‐reference methods,129, 131–133 and calculations in which the reference functions consist of multiple CSFs are called multi‐reference methods 13, 43, 84, 91, 120, 129, 134–136…”

Section: Quantum Mechanical Description Of Chemical Bondingmentioning

confidence: 99%

Valence bond theory for chemical dynamics

Truhlar

2006

J Comput Chem

108

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This essay provides a perspective on several issues in valence bond theory: the physical significance of semilocal bonding orbitals, the capability of valence bond concepts to explain systems with multireferences character, the use of valence bond theory to provide analytical representations of potential energy surfaces for chemical dynamics by the method of semiempirical valence bond potential energy surfaces (an early example of specific reaction parameters), by multiconfiguration molecular mechanics, by the combined valence bond-molecular mechanics method, and by the use of valence bond states as coupled diabatic states for describing electronically nonadiabatic processes (photochemistry). The essay includes both ab initio and semiempirical approaches.

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Section: Quantum Mechanical Description Of Chemical Bondingmentioning

confidence: 99%

Valence bond theory for chemical dynamics

Truhlar

2006

J Comput Chem

108

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“…The limitations of Storey et al (2000) calculations were addressed by Tayal (2008), who included 135 levels of the 3s 2 3p, 3s3p 2 , 3s 2 3d, 3p 3 , 3s3p3d, 3p 2 3d, 3s3d 2 , 3p3d 2 , 3s 2 4s, 3s 2 4p and 3s 2 4d configurations. For the calculation of energy levels and the A-values, he adopted the multi-configuration Hartree-Fock (MCHF) codes of Froese-Fischer (1991) and Zatsarinny & Froese-Fischer (1999), while for the scattering process the semi-relativistic R-matrix code of Berrington, Eissner & Norrington (1995) was used. Furthermore, he calculated values of Ω up to an energy of 150 Ryd, although the range of partial waves adopted (J 25) is insufficient at higher energies, for the convergence of the allowed and some of the forbidden transitions.…”

Section: Introductionmentioning

confidence: 99%

Energy levels, radiative rates and electron impact excitation rates for transitions in Fe xiv

Aggarwal

Keenan

2014

Monthly Notices of the Royal Astronomical Society

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Energies and lifetimes are reported for the lowest 136 levels of Fe XIV, belonging to the (1s 2 2s 2 2p 6 ) 3s 2 3p, 3s3p 2 , 3s 2 3d, 3p 3 , 3s3p3d, 3p 2 3d, 3s3d 2 , 3p3d 2 and 3s 2 4 configurations. Additionally, radiative rates, oscillator strengths and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions. Theoretical lifetimes determined from these radiative rates for most levels show satisfactory agreement with earlier calculations, as well as with measurements. Electron impact excitation collision strengths are also calculated with the Dirac atomic R-matrix code (DARC) over a wide energy range up to 260 Ryd. Furthermore, resonances have been resolved in a fine energy mesh to determine effective collision strengths, obtained after integrating the collision strengths over a Maxwellian distribution of electron velocities. Results are listed for all 9180 transitions among the 136 levels over a wide range of electron temperatures, up to 10 7.1 K. Comparisons are made with available results in the literature, and the accuracy of the present data is assessed.

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“…Froese Fischer [64] The MCHF atomic structure package Methods Froese Fischer [65] MCHF support libraries and utilities Package Froese Fischer, Liu [66] Configuration-state lists Package Hibbert, Froese Fischer [67] Angular integrals with non-orthogonal orbitals Package Froese Fischer [68] General MCHF program Package Hibbert, Glass, Froese Fischer [69] Angular integrals for Breit-Pauli Hamiltonian Package Froese Fischer [70] General CI program Package Froese Fischer, Godefroid, Hibbert [71] Angular integrals for transition operators Package Froese Fischer, Godefroid [72] Programs for LS and LSJ transitions Package…”

Section: Short Title Type Of Papermentioning

confidence: 99%

Charlotte Froese Fischer—Her Work and Her Impact

Hibbert

2019

Atoms

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Charlotte Froese Fischer has been at the forefront of research in atomic structure theory for over 60 years. She has developed many of the methods currently used by researchers and has written associated computer programs which have been published and hence made accessible to the research community. Throughout her career, she has consistently encouraged and mentored young scientists, enabling them to embark on independent careers of their own. This article provides an overview of the methods and codes she has developed, some large-scale calculations she has undertaken, and some insight into the impact she has had on young scientists, and the leadership she continues to show as she reaches her 90th birthday.

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A configuration interaction program

Cited by 64 publications

References 10 publications

Valence bond theory for chemical dynamics

Valence bond theory for chemical dynamics

Energy levels, radiative rates and electron impact excitation rates for transitions in Fe xiv

Charlotte Froese Fischer—Her Work and Her Impact

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