GerritJan Linker

Density matrix A density matrix D can be constructed when using the LCAO ansatz for the creation of MO's. LCAO wavefunction: ψ_{k} = ∑_{i}C_{ik}Ф_{i} , where the sum runs over atomic orbitals that are combined by (we assume real) coefficients C_{ki}. These coefficients form a matrix C for all orbitals k where each row corresponds to a given wavefunction ψ_{k} and where the columns contain the LCAO expansion coefficients. The density matrix D consists of products of coefficients C: D_{ij} = ∑_{p}C_{ip}C_{jp}
