KL edges in x-ray-absorption spectra of third-period atoms: Si, P, S, and Cl

A systematic investigation of double-electron KL-edge resonances in x-ray-absorption spectra of third-period atoms (Si, P, S, and Cl) is presented. Experimental data on NaH2PO4, Grahams salts (Na2O:P2O5), Na4P2O7, elemental S, Na2SO3, K2SO4, CuSO4, Na2S2O3, Na2S2O6, NaClO2, NaClO3, and NH4ClO4 are reported and discussed in combination with previous measurements at the Si KL edge of SiX4, (X=H,CH3,Br,Cl,F) molecules. The further comparison of these results with KL-edge structures in Ne and Ar provides an almost complete overview of these excitations for third-period atoms. A compilation of energies and oscillator strengths for the dominant resonances is reported and the main trends of energy splitting, intensity, and energy position versus oxidation state and Z number are discussed.