Grid-based differential equation solver

Our research funded by the U.S. Department of Energy includes the grid-based general differential equation solver. The emphasis is placed on the Schrödinger equation for many-electron systems. We explore the departure from the widespread LCAO (linear combination of atomic orbitals) expansion and introduce two-electron basis functions, which, in view of the one- and two-electron nature of Hamiltonian, are believed to be the most rational expansion basis for electron correlation problem. We have written a grid-based, numerical solver of Hartree–Fock equation of general polyatomic molecules.