2010/10/12 by B. Andreas, Birk Andreas, Y. Azuma +41 · 219 citations
Chemistry · Decision Sciences · Physics and Astronomy · #Avogadro constant #Chemical Thermodynamics and Molecular Structure #Computer science #Constant (computer programming) #Crystal (programming language) #Ion #Kilogram #Molar mass #Nuclear magnetic resonance #Physics #Planck constant #Quantum #Quantum mechanics #Radioactive Decay and Measurement Techniques #Rydberg constant #Rydberg formula #Scientific Measurement and Uncertainty Evaluation #Theoretical physics #cond-mat.other #physics.atom-ph #physics.chem-ph
paper · pdf · doi:10.1103/physrevlett.106.030801
published in Physical Review Letters 106(3), 030801 (American Physical Society) · 4 pages, 5 figures, 3 tables
arxiv created 2010/10/12 · openalex publication_date 2011/01/18 · openalex created_date 2016/06/24 · arxiv updated 2020/07/17 · openalex updated_date 2026/08/05
The Avogadro constant links the atomic and the macroscopic properties of matter. Since the molar Planck constant is well known via the measurement of the Rydberg constant, it is also closely related to the Planck constant. In addition, its accurate determination is of paramount importance for a definition of the kilogram in terms of a fundamental constant. We describe a new approach for its determination by counting the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope. It enabled isotope dilution mass spectroscopy to determine the molar mass of the silicon crystal with unprecedented accuracy. The value obtained, NA = 6.022,140,78(18) × 10(23) mol(-1), is the most accurate input datum for a new definition of the kilogram.