Abstract
We report new values from Penning trap single ion mass spectrometry for the atomic masses of , , , and with uncertainties , a factor of 100 improvement over the accuracy of previously measured values. We have found , , , and . These values are important for new ppb-level determinations of the molar Planck constant and the fine-structure constant α. With the measurement of we have increased the mass range for sub-ppb measurements by a factor of 3. From and other values we derive .
- Received 19 April 1999
DOI:https://doi.org/10.1103/PhysRevLett.83.4510
©1999 American Physical Society