title: The effect of Li doping on the nonlinear optical properties of [2.2]paracyclophane.
abstract: The similar molecules [2.2]paracyclophane (22PCP) and 1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane (8F22PCP) have both generated considerable synthetic interest since they were first prepared. In this work, the nonlinear optical properties of 22PCP, 8F22PCP, and the related Li-doped systems 22PCP-Li and 8F22PCP-Li (which have a Li atom above 22PCP and 8F22PCP, respectively) were investigated. An analysis of natural bond orbital charges showed that there is greater charge transfer from the Li atom to the benzene rings in 8F22PCP-Li than in 22PCP-Li. The variation in the calculated nucleus independent chemical shift (NICS) value as a function of the distance from the lower benzene ring towards the upper benzene ring was found to be W-shaped for both 22PCP and 22PCP-Li. Moreover, whereas all of the NICS values of 22PCP and 22PCP-Li were markedly negative, all of the NICS values of 8F22PCP and 8F22PCP-Li were either positive or only moderately negative. Calculations of the electro-optical properties of these systems showed that the first hyperpolarizability of 22PCP-Li was noticeably larger than that of 8F22PCP-Li. According to the two-level model, the larger first hyperpolarizability of 22PCP-Li is due to its smaller transition energy.
authors.affiliation: Chemistry and Biology Academy, Beihua University, Jilin, 132013, People's Republic of China. bhhxsg@163.com.
authors.forename: Gang
authors.initials: G
authors.lastname: Sun
authors.affiliation: Chemistry and Biology Academy, Beihua University, Jilin, 132013, People's Republic of China.
authors.forename: Xi-Xin
authors.initials: XX
authors.lastname: Duan
authors.affiliation: College of Chemical Engineering, Northeast Dianli University, Jilin, 132012, People's Republic of China.
authors.forename: Chun-Guang
authors.initials: CG
authors.lastname: Liu
mesh_terms: D008094:Lithium / Q000737:chemistry*; D008956:Models, Chemical; D055095:Optics and Photonics; D011083:Polycyclic Compounds / Q000737:chemistry*
chemical_list: D011083:Polycyclic Compounds; C515344:(2.2)paracyclophane; D008094:Lithium
keywords: Effect of Li doping; Nonlinear optical property; [2.2]Paracyclophane