SEARCH Articles Figures Tables Correlation energy with 40 Hylleraas function Explicitly correlated methods Hylleraas function Helium atom Hylleraas function Hylleraas Hylleraas and James-Coolidge wave functions Hylleraas function compared Hylleraas function methods Hylleraas functions Hylleraas functions Hylleraas wave function Hylleraas-type basis functions The Hylleraas function The Hylleraas functional Total energy with 40 Hylleraas function