Measurement of the Sommerfeld Fine-Structure Constant by Level Crossing in Atomic Hydrogen

Abstract

The Sommerfeld fine-structure constant has been measured in atomic hydrogen by level-crossing spectroscopy at 3484 G. The fine-structure interval is found to be 10 969.15(12) MHz and the fine-structure constant ${\ensuremath{\alpha}}^{\ensuremath{-}1}=137.0353(8)$.