Li 2 Trapped inside Tubiform [ n ] Boron Nitride Clusters ( n =4–8): Structures and First Hyperpolarizability

The geometries and electronic properties of tubiform [ n ] boron nitride clusters entrapping Li 2 (Li 2 @BN‐cluster( n ,0); n =4–8), obtained by doping BN‐cluster( n ,0) with Li 2 molecules, are investigated by means of DFT. The effects of tube diameter n on the dipole moment μ 0 , static polarizability α 0 , and first hyperpolarizability β 0 are elucidated. Both the dipole moment and polarizability increase with increasing tube diameter, whereas variation of the static first hyperpolarizability with tube diameter is not monotonic; β 0 follows the order 1612 ( n =4)<3112 ( n =5)<5534 ( n =7)<8244 ( n =6)<12 282 a.u. ( n =8). In addition, the natural bond orbital (NBO) charges show that charge transfer takes place from the Li 2 molecule to the BN cluster, except for BN‐cluster(8,0) with larger tube diameter. Since the large‐diameter tubular BN‐cluster(8,0) can trap the excess electrons of the Li 2 molecule, Li 2 @BN‐cluster(8,0) can be considered to be a novel electride compound.