Improved generator coordinate Hartree–Fock method: application to first-row atoms

An improved generator coordinate Hartree–Fock (IGCHF) method is proposed as a useful generalization of the generator coordinate Hartree–Fock (GCHF) method. The IGCHF uses two or three sets of basis functions for each symmetry. The two and three sets of exponents are generated from two and three different arithmetic sequences, respectively. Ground state Hartree–Fock calculations for first-row atoms using optimized Gaussian basis sets of the same size, generated with the GCHF and IGCHF methods, are carried out to demonstrate the substantial improvement offered by the IGCHF method.