Direct measurement of fine structure in the ground state of atomic carbon by laser magnetic resonance

Abstract
The fine-structure intervals in the ground 2 3P multiplet of lZC I have been measured with high accuracy by laser magnetic resonance. The results are: AR(3Y2-3P1) = 809.3446 (29) GHz and AE(3Y1-3Po) = 492.1623(7) GHz. These precise nieasurements have made possible the astronomi- cal detection of far-infrared line emissions from I2C atoms in several interstellar sources, as re- ported in the accompanying Letter by Phillips et al. Subject headings: atomic processes - infrared : spectra I. INTRODUCTION