Unusual Manipulative Effects of Spin Multiplicity and Excess Electron Number on the Structure and Nonlinear Optical Response in New Linear and Cyclic Electride Molecules with Multiexcess Electrons

Using the M06-2X density functional theory, unusual manipulative effects of spin multiplicity and excess electron number on the structure and static first hyperpolarizability (β 0 ) are revealed for new electride molecules with multiexcess electrons. (1) For the spin effect on molecular structure, the low spin multiplicity brings bent structures ( 1 L 2 and 2 L 3 ) for linear isomers. (2) For the dramatic effect of spin multiplicity on β 0, the considerable β 0 of 22.7 × 10 4 au for the low spin structure 2 L 3 is larger by 21 times than that of 1.1 × 10 4 au for the high spin structure 4 L 3 due to one excess electron spin reversal. The low spin structure with doubly and singly occupied frontier orbitals is relevant to the low transition energy and complex distribution of electron density, which dramatically enhances β 0 . (3) For the effect of excess electron number on β 0, the β 0 value increases rapidly with increasing excess electron number. A long chain-shaped electride molecule (for instance, 2 L 3 ) with multiexcess electrons in low spin state may bring a considerable static first hyperpolarizability, which is a novel manipulation strategy of enhancing molecular NLO response.