The electron affinity of astatine

D Leimbach ,Reinhard Heinke,Valentin Fedosseev,Julia Karls,Rizwan Ahmed,Lukáš F Pašteka,Nicolas Galland,Lars Bengtsson,Anastasia Borschevsky,Ferran Boix Pamies,Yangyang Guo,Ephraim Eliav,Jessica Warbinek,Jakob Welander,Eric Renault,O Forstner ,R E Rossel ,R F García Ruíz ,K Johnston ,M K Kristiansson ,Á Koszorús ,K Chrysalidis ,M Reponen ,C Granados ,A R Vernon ,Κ Wendt ,J Ballof ,D V Fedorov ,S G Wilkins ,U Köster ,P L Molkanov ,B A Marsh ,J.p Ramos ,A Ringvall-Moberg ,Dag Hanstorp,Yuan Liu,Dominik Studer,S Rothe

doi:10.1038/s41467-020-17599-2

Abstract

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Among the remaining elements with unknown EA is astatine, where one of its isotopes, 211At, is remarkably well suited for targeted radionuclide therapy of cancer. With the At− anion being involved in many aspects of current astatine labeling protocols, the knowledge of the electron affinity of this element is of prime importance. Here we report the measured value of the EA of astatine to be 2.41578(7) eV. This result is compared to state-of-the-art relativistic quantum mechanical calculations that incorporate both the Breit and the quantum electrodynamics (QED) corrections and the electron–electron correlation effects on the highest level that can be currently achieved for many-electron systems. The developed technique of laser-photodetachment spectroscopy of radioisotopes opens the path for future EA measurements of other radioelements such as polonium, and eventually super-heavy elements.

Highlights

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA)
While astatine was discovered in the 1940s10,11, it is only recently that the ionization energy (IE) of astatine was measured through an on-line laser-ionization spectroscopy experiment at CERN-ISOLDE12
We present the experimental determination of the electron affinity of astatine by means of laser photodetachment threshold spectroscopy

Summary

Introduction

One of the most important properties influencing the chemical behavior of an element is the electron affinity (EA). Chemistry is all about molecule formation through the creation or destruction of chemical bonds between atoms and relies on an in-depth understanding of the stability and properties of these molecules. Mulliken used the EA in combination with the ionization energy (IE), the minimum amount of energy required to remove an electron from an isolated neutral gaseous atom, to develop a scale for quantifying the electronegativity of the elements[4]. The usefulness of these concepts for chemists, especially in the field of reactivity, has been amply demonstrated in recent decades[5,6]. While astatine was discovered in the 1940s10,11, it is only recently that the IE of astatine was measured through an on-line laser-ionization spectroscopy experiment at CERN-ISOLDE12

Methods

Results

Conclusion