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arXiv · 1207.7284

Hylleraas-Configuration Interaction calculations on the 1 ^1S ground state of helium atom

Maria Belen Ruiz
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Abstract

Hylleraas-Configuration Interaction (Hy-CI) calculations on the ground $1^1$S state of helium atom are presented using s-, p-, d-, and f-Slater orbitals of both real and complex form. Techniques of construction of adapted configurations, optimization of the orbital exponents and structure of the wave function expansion are explored. A new method to evaluate the two-electron kinetic energy integrals occurring in the Hy-CI method has been tested here and compared with other methods. The non-relativistic Hy-CI values are approximately 10 picohartree accurate, about 2.2 x 10$^{-6}$ cm$^{-1}$. The Hy-CI calculations are compared with Configuration Interaction (CI) and Hylleraas (Hy) calculations employing the same orbital basis set, same computer code and same computer machines. The computational required times are reported.

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Maria Belen Ruiz. 2012-07-31. Hylleraas-Configuration Interaction calculations on the 1 ^1S ground state of helium atom. https://doi.org/10.1080/00958972.2015.1064907

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