Simple method for determining fullerene negative ion formation

Abstract

A robust potential wherein is embedded the crucial core-polarization interaction is used in the Regge-pole methodology to calculate low-energy electron elastic scattering total cross section for the C₆₀ fullerene in the electron impact energy range 0.02 ≤ E ≤ 10.0 eV. The energy position of the characteristic dramatically sharp resonance appearing at the second Ramsauer–Townsend minimum of the total cross section representing stable C₆₀⁻ fullerene negative ion formation agrees excellently with the measured electron affinity of C₆₀ [Huang et al., J. Chem. Phys. 140, 224315 (2014)]. The benchmarked potential and the Regge-pole methodology are then used to calculate electron elastic scattering total cross sections for selected fullerenes, from C₅₄ through C₂₄₀. The total cross sections are found to be characterized generally by Ramsauer–Townsend minima, shape resonances and dramatically sharp resonances representing long-lived states of fullerene negative ion formation. For the total cross sections of C₇₀, C₇₆, C₇₈, and C₈₄ the agreement between the energy positions of the very sharp resonances and the measured electron affinities is outstanding. Additionally, we compare our extracted energy positions of the resultant fullerene anions from our calculated total cross sections of the C₈₆, C₉₀ and C₉₂ fullerenes with the estimated electron affinities ≥3.0 eV by the experiment [Boltalina et al., Rapid Commun. Mass Spectrom. 7, 1009 (1993)]. Resonance energy positions of other fullerenes, including C₁₈₀ and C₂₄₀ are also obtained. Most of the total cross sections presented in this paper are the first and only; our novel approach is general and should be applicable to other fullerenes as well and complex heavy atoms, such as the lanthanide atoms. We conclude with a remark on the catalytic properties of the fullerenes through their negative ions.

Graphical abstract