Scientists' report world's first X-ray of a single atom

Amazing stuff! The discovery in 1895 by Wilhelm Röntgen keeps on giving!

Unfortunately, for now you need a very special facility to do this kind of research!

"Using powerful X-ray machines called synchrotron light sources, scientists can analyze samples as small as a billionth of a billionth of a gram. Such samples contain about 10,000 atoms. Smaller sizes have proved exceedingly difficult to achieve, but in an astonishing leap, the team managed to scale down their observations to a single atom."

"A team of scientists ... have taken the world's first X-ray SIGNAL (or SIGNATURE) of just one atom. This groundbreaking achievement could revolutionize the way scientists detect the materials. ...
"Atoms can be routinely imaged with scanning probe microscopes, but without X-rays one cannot tell what they are made of. We can now detect exactly the type of a particular atom, one atom-at-a-time, and can simultaneously measure its chemical state," ..."

From the abstract:

"Since the discovery of X-rays by Roentgen in 1895, its use has been ubiquitous, from medical and environmental applications to materials sciences. X-ray characterization requires a large number of atoms and reducing the material quantity is a long-standing goal. Here we show that X-rays can be used to characterize the elemental and chemical state of just one atom. Using a specialized tip as a detector, X-ray-excited currents generated from an iron and a terbium atom coordinated to organic ligands are detected. The fingerprints of a single atom, the L2,3 and M4,5 absorption edge signals for iron and terbium, respectively, are clearly observed in the X-ray absorption spectra. The chemical states of these atoms are characterized by means of near-edge X-ray absorption signals, in which X-ray-excited resonance tunnelling (X-ERT) is dominant for the iron atom. The X-ray signal can be sensed only when the tip is located directly above the atom in extreme proximity, which confirms atomically localized detection in the tunnelling regime. Our work connects synchrotron X-rays with a quantum tunnelling process and opens future X-rays experiments for simultaneous characterizations of elemental and chemical properties of materials at the ultimate single-atom limit."

Scientists' report world's first X-ray of a single atom

Scientists analyze a single atom with X-rays for the first time New X-ray capability could find wide application in environmental and medical research, as well as the development of batteries and microelectronic devices. In the most powerful X-ray facilities in the world, scientists can analyze samples so small they contain only 10,000 atoms. Smaller sizes have proved exceedingly difficult to achieve, but a multi-institutional team has scaled down to a single atom.

Characterization of just one atom using synchrotron X-rays (no public access)

Left: Image of a ring-shaped molecular host that contains just one iron atom. Right: X-ray absorption spectrum of single atom detected at location B in the molecular ring. Spectrum matches that of iron. (Image by Argonne National Laboratory.)