Chen De-Li, Tian Wei Quan, Feng Ji-Kang, Sun Chia-Chung
State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
J Chem Phys. 2007 Feb 21;126(7):074313. doi: 10.1063/1.2646979.
The 437 classical isomers of fullerene C52 have been studied by PM3, HCTH/3-21G, and B3LYP6-31G(d). C(2):029 with the least number of adjacent pentagons is predicted to be the most stable isomer. The investigations show that both the number of adjacent pentagons and the degree of aromaticity play important roles in the relative stabilities of fullerene isomers. To clarify the relative stabilities of the C52 isomers in a wide range of temperatures, the entropy contributions are taken into account on the basis of the Gibbs energy at the B3LYP6-31G(d) level. C(2):029 prevails in a wide temperature range. In addition, the electronic spectra and second-order hyperpolarizabilities are determined by means of ZINDO and sum-over-states model. The static second-order hyperpolarizability of C(2):029 is 51% larger than that of C60. Furthermore, intensity-dependent refractive index gamma (-omega;omega,omega,-omega) (omega=1.1653 eV) of C(2):029 is 13 times larger than that of C60. The encapsulation of Ca atom in C52 fullerene is exothermic and the metallofullerene Ca-C52 is described as Ca2+-C52(2-).
已通过PM3、HCTH/3-21G和B3LYP6-31G(d)方法研究了富勒烯C52的437种经典异构体。预测相邻五边形数量最少的C(2):029为最稳定的异构体。研究表明，相邻五边形的数量和芳香性程度在富勒烯异构体的相对稳定性中都起着重要作用。为了阐明C52异构体在较宽温度范围内的相对稳定性，基于B3LYP6-31G(d)水平的吉布斯自由能考虑了熵的贡献。C(2):029在很宽的温度范围内占主导地位。此外，通过ZINDO和态叠加模型确定了电子光谱和二阶超极化率。C(2):029的静态二阶超极化率比C60大51%。此外，C(2):029的强度依赖折射率γ(-ω;ω,ω,-ω)(ω = 1.1653 eV)比C60大13倍。Ca原子封装在C52富勒烯中是放热的，金属富勒烯Ca-C52被描述为Ca2+-C52(2-)。
