In practice, CI calculations involve several steps:
1. Selection of Basis Set: A set of functions used to describe the molecular orbitals. 2. Hartree-Fock Calculation: Initial approximation to obtain a reference wavefunction. 3. Construction of Excited Configurations: Generate configurations by promoting electrons to higher energy orbitals. 4. Diagonalization of Hamiltonian Matrix: Solve the Schrödinger equation to obtain the energy levels and wavefunctions of the system.
