Absolute wavelength measurement of the Lyman-α transition of hydrogen-like silicon

Abstract

The wavelengths of the 1s1/2–2p1/2 and 1s1/2–2p3/2 Lyman-α transitions have been measured in hydrogenic silicon with an accuracy of 70 ppm. The measurement was carried out with an electron-beam ion trap with a calibrated double-faced monolithic crystal that enabled absolute measurements of the transition wavelengths. The values for the Lyman-α wavelengths are λLyα1 = 6.180 49(44) Å and λLyα2 = 6.185 56(66) Å. The wavelengths are in good agreement with calculations and allow a determination of the 1s Lamb shift to within 28% in a region that has received little experimental attention. PACS Nos.:32.30Rj, 31.30Jv