Paper by Szalewicz group paves the way for greater precision in pressure measurement

May 1, 2015 - Most of us know helium as the lighter-than-air gas that puts lift into birthday balloons or makes a baritone's resonant voice sound more like Donald Duck's. But helium -- a non-toxic element that is abundant in the universe but a scarce, non-renewable resource on earth -- has many significant uses in industry, medicine and science.

Researchers at the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland, have proposed an improved method for measuring pressure by using helium rather than mercury. Mercury-based manometers/barometers are the standard tools of measurement, but helium-based approach offers significant advantages by avoiding the use of toxic mercury and making measurement devices more portable and more precise than those currently in use.

In an article published this week by Physical Review Letters, University of Delaware physics professor Krzysztof Szalewicz and his collaborators from the University of Warsaw and the University of Poznan show how they calculated a key property of the helium atom needed for a precise helium-based barometer -- its "polarizability" -- at a level of precision 100 times greater than previously possible either experimentally or computationally.