Determination of the Avogadro Constant
Abstract
Measurements are reported on the densities and isotopic-abundance ratios of nearly perfect Si single crystals. These, when combined with optical interferometry of the crystal repeat distance, yield a new value for the Avogadro constant. This result, NA=6.022 094 3×1023 mol-1 (1.05 ppm), represents a more than thirty-fold reduction in the uncertainty of previous direct measurements.
- Publication:
-
Physical Review Letters
- Pub Date:
- August 1974
- DOI:
- 10.1103/PhysRevLett.33.463
- Bibcode:
- 1974PhRvL..33..463D