In this section configuration interaction methods will be described.
The CI singles are done by building a Hamiltonian and diagonalizing it. The Hamiltonian build accourding to:
Here everything is in spin orbital basis.
- CI.CIS(occ, F, C, VeeMOspin)
- return Exc
- occ, number of occupied MOs in spinbasis
- F, fock matrix in spatial basis
- C, MO coeffcients in spatial basis
- VeeMOspin, MO integrals in spin basis
- Exc, single excitation energies