Negative ion formation in lanthanide atoms: Many-body effects

TL;DR

This study investigates negative ion formation in lanthanide atoms using the complex angular momentum method, revealing the importance of many-body effects and providing new electron affinity values with implications for nanocatalysis.

Contribution

It introduces a reliable computational approach to determine negative ion properties of lanthanides, resolving previous discrepancies and offering new data for environmental applications.

Findings

Resolved the discrepancy in Eu electron affinity measurements.

Identified shape resonances and binding energies of lanthanide anions.

Provided new electron affinity values for Nd, Tb, and Tm.

Abstract

Investigations of low-energy electron-scattering of the lanthanide atoms Eu, Nd, Tb, Tm demonstrate that electron-correlation effects and core polarization are the dominant fundamental many-body effects responsible for the formation of metastable states of negative ions. Ramsauer Townsend minima, shape resonances and binding energies of the resultant anions are identified and extracted from the elastic total cross sections calculated using the complex angular momentum method. The large discrepancy between the recently measured electron affinity of 0.116 and the previously measured value of 1.053 eV for Eu is resolved. Also, the previously measured electron affinities for Nd, Tb and Tm are reconciled and new values are extracted from the calculated total cross sections. The large electron affinities found here for these atoms, should be useful in negative ion nanocatalysis, including methane conversion to methanol without CO2 emission, with significant environmental impact.. The powerful complex angular momentum method which requires only a few poles, yields reliable binding energies for the metastable states of negative ions with no a priori knowledge of experimental or other theoretical data and should be applicable to other complex systems for the fundamental understanding of their interactions.