多电荷C70富勒烯稳定性的理论研究

Theoretical study of the stability of multiply charged C70 fullerenes.

作者信息

Zettergren Henning, Sánchez Goar, Díaz-Tendero Sergio, Alcamí Manuel, Martín Fernando

机构信息

Departamento de Química, C-9, Universidad Autónoma de Madrid, 28049 Madrid, Spain.

出版信息

J Chem Phys. 2007 Sep 14;127(10):104308. doi: 10.1063/1.2768361.

DOI:10.1063/1.2768361

PMID:17867748

Abstract

We have calculated the electronic energies and optimum geometries of C(70) (q+) and C(68) (q+) fullerenes (q=0-14) by means of density functional theory. The ionization energies for C(70) and C(68) fullerenes increase more or less linearly as functions of charge, consistent with the previously reported behavior for C(60) and C(58) [S. Diaz-Tendero et al., J. Chem. Phys. 123, 184306 (2005)]. The dissociation energies corresponding to the C(70) (q+)-->C(68) (q+)+C(2), C(70) (q+)-->C(68) ((q-1)+)+C(2) (+), C(70) (q+)-->C(68) ((q-2)+)+C(+)+C(+), C(70) (q+)-->C(68) ((q-3)+)+C(2+)+C(+), and C(70) (q+)-->C(68) ((q-4)+)+C(2+)+C(2+) decay channels show that C(70) (q+) (like C(60) (q+)) is thermodynamically unstable for q>or=6. However, the slope of the dissociation energy as a function of charge for a given decay channel is different from that of C(60) (q+) fullerenes. On the basis of these results, we predict q=17 to be the highest charge state for which a fission barrier exists for C(70) (q+).

摘要

我们通过密度泛函理论计算了C(70)(q+)和C(68)(q+)富勒烯（q = 0 - 14）的电子能量和最佳几何结构。C(70)和C(68)富勒烯的电离能随电荷大致呈线性增加，这与之前报道的C(60)和C(58)的行为一致 [S. Diaz - Tendero等人，《化学物理杂志》123, 184306 (2005)]。对应于C(70)(q+)→C(68)(q+)+C₂、C(70)(q+)→C(68)((q - 1)+)+C₂⁺、C(70)(q+)→C(68)((q - 2)+)+C⁺+C⁺、C(70)(q+)→C(68)((q - 3)+)+C₂⁺+C⁺以及C(70)(q+)→C(68)((q - 4)+)+C₂⁺+C₂⁺衰变通道的解离能表明，对于q≥6，C(70)(q+)（类似于C(60)(q+)）在热力学上是不稳定的。然而，给定衰变通道的解离能随电荷变化的斜率与C(60)(q+)富勒烯的不同。基于这些结果，我们预测q = 17是C(70)(q+)存在裂变势垒的最高电荷态。