An experimental atomic physicist who coauthored measurements of the gravitational deflection of long atomic beams. Slower potassium and caesium chemical atoms spend longer in flight and fall farther; the beam's vertical intensity profile therefore reveals its velocity distribution. The experiment turned a small gravitational displacement into a measurement of thermal beam statistics.[ref]
The Free Fall of Atoms and the Measurement of the Velocity Distribution in a Molecular Beam of Cesium Atoms by Immanuel Estermann, Oliver Cecil Simpson, and Otto Stern. Abstract: gravitational deflection and modified Maxwellian velocity distribution