Spectrum and energy levels of singly ionized aluminum (Al ii)

Abstract

New wavelength measurements in the spectrum of singly ionized aluminum (8640–683 Å) have been combined with some previous observations to re-evaluate all of the known energy levels of that ion. The designations of the previously known 3p 3d3D0 and 3P0 terms have been changed and newly found terms have been identified as 3p 3d3D0 and 3p21S. The ionization energy is 151862.7(4) cm−1 or 18.828 73(5) eV.