Avogadro Constant: 201 Years of Counting Molecules
Department of Physical Chemistry, Institute of Chemical Technology, Prague
A brief history of molecule counting in the last two centuries is described. The story started with early determinations of the Avogadro constant by Loschmidt and others and ends for the time being with its modern spectroscopic determinations. The relation of high-precision Avogadro constant measurements to modern metrology is discussed in the context of recent suggestions of reforms in the SI unit system.
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