The lithium‐orientation effect on the hyperpolarizability in the short zigzag‐edged monolithiated aza‐Möbius graphene ribbon [2,7] isomers

In the short zigzag‐edged aza‐Möbius graphene ribbon [2,7], a Li atom monosubstitutes the end H atom from the knot subring (1) to the subring (7), respectively, seven structures of short monolithiated aza‐Möbius graphene ribbon isomers [MöLi (1), MöLi (2), MöLi (3), MöLi (4), MöLi (5), MöLi (6), and MöLi (7)] with all the real frequencies are obtained at the B3LYP/6‐31G (d) level. The results of the static first hyperpolarizabilities (β 0 ) show that lithiation effect on β 0 is obvious. The β 0 value of MöLi (4) (1019 a.u.) is about 4 times of 250 a.u. of the aza‐Möbius graphene ribbon. For the lithiated Möbius isomers, the lithium‐orientation effect is exhibited. The lithiated subring is or near the knot subring, the isomers [MöLi (1), MöLi (2), and MöLi (7)] have small β 0 values, while that is far away from the knot subring, the isomers [MöLi (4) and MöLi (5)] have large β 0 values. For the MöM (1) (M = Li, Na, and K), the alkali atomic number dependence for the static hyperpolarizability (α 0 ) and β 0 is found that both the α 0 and β 0 value increase with increasing the alkali atomic number in the orders of 275.27 (M = Li) < 279.75 (M = Na) < 284.77 a.u. and 352 (M = Li) < 590 (M = Na) < 706 a.u. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011