VUV photoabsorption and photoemission of atomic Cr

The photoabsorption and photoemission of atomic Cr have been obtained in the photon energy range 30 to 70 eV. At the 3p threshold the spectrum is dominated by 3p 6 3d 5 4s( 7 S) to 3p 5 3d 5 4s 2 ( 7 P), 3p 5 3d 6 4s ( 7 F, 7 D, 7 P) transitions giving rise to discrete absorption lines and a broad asymmetric absorption band. In contrast to the higher-Z members of the 3d transition metal series the Cr 3p absorption spectrum shows three well developed 3p 6 3d 5 4s to 3p 5 3d 5 4snd Rydberg series converging towards the 3p 5 3d 5 4s 8 P 5/2,7/2,9/2 states of Cr II. The 3d 4 4s 6 D and 3d 5 6 S photoemission lines are strongly enhanced above the 3p threshold. As a function of photon energy the intensity of the 3d 5 6 S line shows a symmetric profile, whereas the 3d 4 4s 6 D line is clearly asymmetric thus corroborating the interference between 3p and 3d excitations. Asymmetric profiles are also displayed by the two 3d 4 4p 6 F, 3d 4 5s 6 D photoemission lines.