Measurement of the 2/sup 3/P/sub 0/-2/sup 3/P/sub 1/ helium fine structure interval

Abstract

In this paper we describe a measurement of the helium 2/sup 3/P/sub 0/-/sup 2/3P/sub 1/ interval, obtained from a full optical approach in an atomic beam of metastable He. Direct frequency determination and control of systematic effects leads to an accuracy of 3 kHz. By comparison with a precise atomic theory, a 50 ppb accurate determination of the fine structure constant /spl alpha/ will be possible.