Double excitation in the K absorption spectrum of neon

The high resolution spectrum of gaseous neon in the 1s region was obtained by using synchrotron radiation. In addition to previously observed single-electron excitation lines, the authors observed two new sharp lines of comparable intensities in the continuum at 35.1 and 38.1 eV above the 1s to 3p resonance line. On the basis of the known Ne 1s XPS shake-up lines the authors attribute them to transitions to 1 P 0 levels of the 1s2s 2 2P 5 3p 2 final-state configuration.