Theoretical study on the second hyperpolarizabilities of one-dimensional heteronuclear transition-metal-metal bonded systems: Metal alignment effects

- Second hyperporizabilities (γ) of transition-metal heterotetranuclear systems.
- Metal alignment effects on the diradical character (y) dependence of the γ.
- The y values in the tetranuclear systems can be controlled by the metal alignment.
- dσ electrons contribute to the enhancement of γ in the intermediate y region.