Molecular orbital analysis based on fragment molecular orbital scheme

Dipole and quadrupole moments computed in the fragment molecular orbital (FMO) scheme reproduce the results from the full molecular orbital (MO) theory within a few percent error. It is also shown that the FMO molecular orbitals for creating the FMO density matrix of each fragment provide qualitatively correct information on the chemical active sites of molecular aggregates in comparison with the full MO counterpart. The FMO also provides correct HOMO for single strand DNA, while the ordering of the LUMO among the fragments is not correct.