The structure and large nonlinear optical properties of a novel octupolar electride Li@36Adz

•The original and interesting concept of octupolar electride (Li@36Adz) is first proposed for nonlinear optics.•Li@36Adz has a very large first hyperpolarizability, up to 1787×10-30 esu at the restricted open-shell second-order Møller-Plesset (ROMP2) level.•Due to the low ionization potential (1.84 eV), Li@36Adz can be seen as superalkalies.

Based on the synthesized H@36Adz (36Adz = 36 adamanzane), a new class of three-dimensional (3D) octupolar molecule Li@36Adz with electride characteristics is first designed and studied with theoretical tools, in which the electron of the encapsulated Li atom is extruded from the cage of 36Adz forming diffused excess electron. Due to S4 symmetry, Li@36Adz only has the octupolar hyperpolarizability (βJ=3) up to 1787 × 10−30 esu at the restricted open-shell second-order Møller-Plesset (ROMP2) level, whose β is about 1787 times more than that (1 × 10−30 esu) of its analogue (H@36Adz). Interestingly, we find that both Li@36Adz has a very low ionization potential (1.84 eV) which can be seen as superalkalies. The present investigations will enrich the concept of 3D octupolar molecules for high-performance NLO materials and offer a method to construct superalkalies.

Graphical abstractThe original and interesting concept of octupolar electride (Li@36Adz) is proposed for nonlinear optics. And this class of molecules exhibits giant first hyperpolarizability.Download full-size image