photos of researchers looking at the field ion microscope and an image made from the field ion microscope

"Atoms, ja, atoms!"

Physicist Erwin Mueller was first to "see" the elemental particle of matter.

professor and graduate student looking at a field ion microscope

The field ion microscope, which enabled physicist Erwin Mueller, left, and doctoral student Kanwar Bahadur to become the first persons to "see" an atom.

Tuesday, October 11, 1955. Penn State’s students that day received a stern warning from the athletic department against scalping their tickets to Saturday’s football game with Navy. Phi Sigma Upsilon made formal application to become the University’s 54th fraternity. The romance languages department and the Spanish Club made final preparations for the Columbus Day program they were co-sponsoring. In Osmond Lab, Professor of Physics Erwin Mueller and his graduate students were making history.

Mueller had come to Penn State four years earlier from his native Germany. An experienced academic researcher, he had earned international acclaim for his invention of the field emission microscope in 1936 and the higher-resolution field ion microscope 15 years later. Both instruments were technological milestones in a quest dating back to the ancient Greeks to identify and observe the tiniest building blocks of matter, although Mueller had failed to image the illusive atom with either instrument.

That changed on October 11 when Mueller and Ph.D. candidate Kanwar Bahadur became the first persons to “see” an atom, using the Mueller-designed field-ion microscope. The two did not realize it immediately, but it was how Bahadur prepared the sample—a sharp-tipped tungsten specimen—that enabled the microscope to provide the first sharp, clear views of crystals on an atomic scale, showing individual atoms and their arrangement on the surface.

professor pointing to black and white image made from the field ion microscope

In this 1968 photo Mueller points to an image made from the new atom-probe field ion microscope, which revealed the chemical identity of individual atoms.

“This is it!” Mueller declared, upon seeing the image of the tungsten atoms on the microscope screen. He departed the lab amid a flurry of excitement, exclaiming in German, “Atoms, ja, atoms!”

There was speculation in the international scientific community at the time that Mueller’s achievement was worthy of a Nobel prize. Similar speculation arose after his 1967 invention of an atom-probe field ion microscope, which advanced microscopy even further with its ability to separate a single atom from surrounding atoms and identify it by its mass.

But such vaunted recognition was not to be. Mueller did receive numerous other awards—he became the first Penn State faculty member to receive the prestigious National Medal of Science—and certainly he secured his place as a pioneer in what would become nanoscale science and technology. He remained at the University, pursuing research and mentoring graduate students, until his death in 1977. Penn State subsequently honored him by naming Mueller Laboratory, and with support from alumni and friends established the Erwin W. Mueller Memorial Lecture in Physics and the Erwin Mueller Professorship in Physics.

the outside of the Mueller Laboratory building

Mueller Laboratory, named for Erwin Mueller
in 1978.

Watch a video with rare color footage of Dr. Mueller and his field ion microscope at
http://live.psu.edu/youtube/3WmzJl2HthQ

For a historical timeline of research in nanoscale science and technology at Penn State, visit
http://www.gonano.psu.edu/history/timeline.asp

For more details on how Mueller came to “see” and atom, and the implications of his historic achievement, visit
http://pubs.acs.org/cen/coverstory/83/8348atoms.html

—Michael Bezilla