title: Theoretical study on the photophysical properties of hexapyrrolidine C60 adducts with Th, D3, and S6 symmetries.
abstract: The equilibrium geometries of three isomeric hexapyrrolidine C(60) adducts with T(h), D(3), and S(6) symmetries are optimized by means of the B3LYP method at the 6-31G basis sets in this paper. On the basis of the optimized structures, the excited state and third-order nonlinear optical properties, such as third-harmonic generation (THG), electric-field-induced second-harmonic generation (EFISHG), and degenerate four-wave mixing (DFWM), and two-photon absorption (TPA) cross sections, delta, are calculated by using the TDB3LYP model based on the 6-31G level coupled with the sum-over-states (SOS) method. The computational results show that the transition energies from S(0) to S(1) of the T(h) hexaadduct and the D(3) hexaadduct have a remarkable blue shift by comparison with that of the C(60) parent. These results are in agreement with experimental ones. However, the first singlet excitation energy of the S(6) hexaadduct has a red shift compared with that of the C(60) parent. Accordingly, we predict that different positions located by six addends may result in the different spectrum properties. Finally, the two-photon absorption cross sections indicate that the largest average value of resonant TPA, delta, of the D(3) hexaadduct has a red shift compared with those of the T(h) and S(6) hexaadducts.
authors.affiliation: Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, State Key Laboratory of Structural Chemistry, Fuzhou, Fujian 350002, People's Republic of China.
authors.forename: X-D
authors.initials: XD
authors.lastname: Li
authors.forename: W-D
authors.initials: WD
authors.lastname: Cheng
authors.forename: D-S
authors.initials: DS
authors.lastname: Wu
authors.forename: Y-Z
authors.initials: YZ
authors.lastname: Lan
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Gong
authors.forename: F-F
authors.initials: FF
authors.lastname: Li
authors.forename: J
authors.initials: J
authors.lastname: Shen