Negative Ion Binding Energies in Complex Heavy Systems

Abstract

We review briefly the recent progress in the determination of accurate and reliable electron affinities (EAs) of complex heavy systems with the view of assessing the reliability of the existing measured and/or calculated EAs of these systems. We demonstrate using slow electron collisions with complex heavy systems a novel and robust approach to the determination of reliable EAs from negative ion formation. From the Regge-pole calculated elastic total cross sections (TCSs), characterized by Ramsauer-Townsend (R-T) minima, shape resonances and dramatically sharp resonances manifesting anionic formation, we extract the anionic binding energies (BEs) for the ground, metastable and excited anionic states formed during the collisions. The ground state anionic BEs located at the absolute values of the R-T minima are identified with the systems' EAs. Results for various complex heavy systems, including fullerene molecules are compared with available measurements and calculations.

Fullerene Negative Ions: Formation and Catalysis

“…Indeed, for the ground state collisions the extracted from the TCSs anionic BEs correspond to the EAs of the fullerenes. The Regge-pole calculated TCSs for the C 60 fullerene presented in Figure 1b is taken from [39]. The TCSs, typical of those calculated in this paper, are found to be characterized generally by dramatically sharp resonances manifesting ground, metastable and excited anionic formation during the collisions, Ramsauer-Townsend (R-T) minima and shape resonances.…”

“…The low-energy electron elastic collision TCSs of the fullerene molecules obtained in this paper as well as those of the already studied fullerenes [18,19,35,36] and the actinide [37] and the lanthanide [38,39] atoms should contribute to a better understanding of the role of the individual atoms/fullerenes in ongoing studies involving endohedral systems [40][41][42][43][44][45][46]. Additionally, expected to benefit from this study will be the exploration of the M@C 60 (M = Ti, Zr,U) fullerene hybrids that have demonstrated catalytic efficiency in fundamental hydrogenation [47].…”

Fullerene Negative Ions: Formation and Catalysis

“…The Regge-pole calculated TCSs for the C60 fullerene presented in Fig. 1(b) is taken from [39]. The TCSs, typical of those calculated in this paper, are found to be characterized generally by dramatically sharp resonances manifesting ground, metastable and excited anionic formation during the collisions, Ramsauer-Townsend (R-T) minima and shape resonances.…”

“…1(b) the C60 TCSs appear complicated as well. However, they are readily understood and interpreted as was done in [19] and [39]. This ground state TCS is clearly shown alone in Fig.…”

“…The low-energy electron elastic collision TCSs of the fullerene molecules obtained in this paper as well as those of the already studied fullerenes [18,19,35,36] and the actinide [37] and the lanthanide [38,39] atoms should contribute to a better understanding of the role of the individual atoms/fullerenes in ongoing studies involving endohedral systems [40][41][42][43][44][45][46]. Also expected to benefit from this study will be the exploration of the M@C60 (M = Ti, Zr, U) fullerene hybrids that have demonstrated catalytic efficiency in fundamental hydrogenation [47].…”