natural hybrid orbital

https://doi.org/10.1351/goldbook.NT07078
Symmetrically orthogonalised directed @HT07049@ derived through unitary @T06446@ of natural atomic orbitals centred on a particular atom.
Source:
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1954 [Terms] [Paper]