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Publications Influence

Hylleraas-configuration-interaction analysis of the low-lying states in the three-electron Li atom and Be + ion

- M. B. Ruiz, J. T. Margraf, A. M. Frolov
- Physics
- 22 February 2013

The total energies of 28 bound S, P , D, F , G, H ,a ndI states in the three-electron Li atom and Be + ion, respectively, are determined with the use of the configuration interaction (CI) with Slater… Expand

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Hylleraas–Configuration Interaction calculations on the 11S ground state of helium atom

- M. B. Ruiz
- Chemistry, Physics
- 31 July 2012

Hylleraas–Configuration Interaction (Hy–CI) calculations on the ground 11S state of helium atom are presented using s-, p-, d-, and f-Slater orbitals of both real and complex form. Techniques of… Expand

5 1- PDF

Hylleraas Method for Many-Electron Atoms. I. The Hamiltonian

- M. B. Ruiz
- Physics
- 2005

A general expression for the nonrelativistic Hamiltonian for n-electron atoms with the fixed nucleus approximation is derived in a straightforward manner using the chain rule. The kinetic energy part… Expand

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Hylleraas Method for Many-Electron Atoms. II. Integrals Over Wave Functions With One Interelectronic Coordinate

- M. B. Ruiz
- Physics
- 2005

A procedure is proposed to evaluate matrix elements containing rij linked with angular functions. Using this procedure, the different types of two-, three-, and four-electron radial and angular… Expand

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Evaluation of Hylleraas-CI atomic integrals by integration over the coordinates of one electron. I. Three-electron integrals

- M. B. Ruiz
- Mathematics
- 8 January 2009

A method to evaluate the nonrelativistic electron-repulsion, nuclear attraction and kinetic energy three-electron integrals over Slater orbitals appearing in Hylleraas-CI (Hy-CI) electron structure… Expand

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Bound state spectrum of the triplet states in the Be atom

- A. M. Frolov, M. B. Ruiz
- Chemistry, Physics
- 9 October 2013

Abstract The bound state spectrum of the low-lying triplet states in the Be atom is investigated. In particular, we perform accurate computations of the bound triplet S , P , D , F , G , H and I… Expand

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Fourier-Legendre expansion of the one-electron density matrix of ground-state two-electron atoms.

- S. Ragot, M. B. Ruiz
- Physics, Medicine
- The Journal of chemical physics
- 30 September 2008

The density matrix rho(r,r(')) of a spherically symmetric system can be expanded as a Fourier-Legendre series of Legendre polynomials P(l)(cos theta=rr(')rr(')). Application is here made to… Expand

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Evaluation of Hylleraas-CI atomic integrals. III. Two-electron kinetic energy integrals

- M. B. Ruiz
- Mathematics
- 11 September 2011

This paper is the part III of a series about the evaluation of Hylleraas-Configuration Interaction (Hy-CI) integrals by the method of direct integration over the interelectronic coordinates. The… Expand

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Progress in Hylleraas-CI Calculations on Boron

- M. B. Ruiz
- Physics
- 2012

Preliminary results on Hylleraas-Configuration Interaction calculations of the boron atom ground state are presented. The wave function consists of a 954 term Configuration Interaction part and 192… Expand

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Analytical expressions of exchange and three-center nuclear attraction integrals over 1s and 2s Slater orbitals with different exponents

- M. B. Ruiz, Katrin Peuker
- Physics
- 5 September 2005

Abstract Compact analytical formulas are given for exchange integrals and three-center nuclear attraction integrals using nonorthogonal Slater orbitals with equal and different exponents which appear… Expand

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