Inter-subshell correlations and simultaneous ejection of two photoelectrons in the absorption spectrum of Ga I

Abstract

The absorption spectrum of gallium vapour between 320 and 1000 Å has been investigated for the first time; more than 90 transitions have been detected between 440 and 660 Å. The most intense of these are attributed to excitation of an electron from the 3d subshell but many features occur through simultaneous excitation of two valence electrons and derive their intensity from correlations with the single electron transitions. The concept of at 3d-core ‘hole’ in Ga I is shown to break down near the threshold for simulaneous ejection of two photoelectrons.