Hard x-ray photoelectron spectroscopy on heavy atoms and heavy-element containing molecules using synchrotron radiation up to 35 keV at SPring-8 undulator beamlines

We have recently initiated hard x-ray photoelectron spectroscopy experiments on heavy atoms and heavy-element containing molecules in gas phase by using synchrotron radiation up to 35 keV at SPring-8 undulator beamlines. We have successfully measured deep inner-shell photoelectron spectra, as well as L-MM and M-NN Auger electron spectra excited below and above the K-edge of heavy elements. Target specimens utilized for the preliminary experiments are Ar, Kr and Xe atoms, and also iodine in iodomethane (CH3I) and trifluoroiodomethane (CF3I) molecules, respectively. We show some selected results on the extracted core-hole lifetime broadenings for the iodine 1s core level of the CH3I molecule and also for the Xe 2s, 2p core levels, to compare with theoretical values. The L-MM Auger electron spectra of Kr recorded at 13 and 16.6 keV excitation energies are also shown as typical examples, and the spectrum measured above the K-edge, i.e. 14.327 keV, is analyzed based on theoretical calculations using the Hartree-Fock method. As a result, we give a tentative assignment for the double-core-hole hyper-satellite LL-LMM Auger transitions of the Kr atom.