Adaptive Trust-radius Self-consistent Field for Restricted Open-Shell Hartree-Focks, Restricted Hartree-Focks, and Unrestricted Hartree-Focks

A black-box, general purpose quadratic self-consistent field code with and without Cholesky Decomposition of the two-electron integrals

We present the implementation of a quadratically convergent self-consistent field (qcscf) solver based on an adaptive trust-radius optimization scheme for restricted open-shell hartree-fock (rohf), restricted open-shell hartree-fock (rhf), and unrestricted open-shell hartree-fock (uohf) references.The algorithm can exploit cholesky decomposition (cd) of the two-electron integrals to allow calculations on larger systems.As shown for pilot applications, it does not require one to tune the self-consistent field parameters (damping, pulay s diis, and other similar techniques) in difficult-to-converge molecules.Also, it can be used to obtain a very good convergence with extended basis set-a situation often needed when computing high-order molecular properties-where the standard self-consistent field algorithm starts to oscillate.We discuss what can go wrong even with a qcscf solver.