2012/07/31 by María Belén Ruiz, Maria Belen Ruiz
Chemistry · Physics and Astronomy · #Advanced Chemical Physics Studies #Atom (system on chip) #Atomic orbital #Atomic physics #Basis set #Chemistry #Computational chemistry #Configuration interaction #Density functional theory #Electron #Electron configuration #Excited state #Ground state #Helium #Helium atom #Molecular Spectroscopy and Structure #Molecular orbital #Molecular orbital theory #Molecule #Multireference configuration interaction #Physics #Quantum mechanics #Quantum, superfluid, helium dynamics #Slater-type orbital #Wave function #physics.atom-ph
paper · pdf · doi:10.1080/00958972.2015.1064907
published as Journal of Coordination Chemistry 68(17-18):3340-3361 (2015) · 33 pages, 9 tables, 38 references and 0 figures
openalex publication_date 2015/06/29 · arxiv created 2016/01/28 · arxiv updated 2016/01/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 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 in this work and compared with other methods. The non-relativistic Hy–CI energy values are ≈10 picohartree accurate, about 2.2 × 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.