Young's experiment in a hydroge...( An international investigation invol...)

An international investigation involving the participation of the Consejo Superior de Investigaciones Cientficas (CSIC) has reproduced the experiment of Thomas Young in a molecule of hydrogen, the smallest molecular system that exists. In 1803 the English scientist tested a pattern of interferences in light from a distant source, on passing through a double slit and thus being refracted. This finding confirmed the theory that light had wave motion properties. The authors of this current research, which appears in the latest issue of the journal Science, uses electrons instead of light and the nuclei of the hydrogen molecule as emitting slits.

CSIC researcher Ricardo Dez, Vicedirector of the Centre for Materials Physics (a mixed body of the CSIC and the University of the Basque Country in Donostia-San Sebastin and co-author of the article, explains their experiment: These interference patterns are the same as those produced, on a large scale, when sunlight passes through Persian blinds, throwing shadow patterns and, as it were, games, on the walls. This phenomenon is due to the fact that (light) particles, as with electrons, can also have wave motion behaviour.

At much smaller sizes, atomic planes can create interferences in the transmission of X rays, thus providing information about the internal structure of materials. This is the fundamental basis of the experimental techniques such as X ray diffraction, thanks to which the DNA double helix structure was discovered. Ricardo Dez explains, The Laws that predict, for example, the trajectory of a car at a certain speed are not those that govern the behaviour of atomic-sized particles. On a nanometric scale sizes are measured in units a thousand million times smaller than a metre, and the behaviour of objects at this scale can prove to be surprising, almost magical even!

The experiment

The researchers reproduced Youngs experiment in the smallest system existing - a molecule of
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