X-ray spectroscopy investigation of hydrogen-containing phases based on the compounds of tungsten with VI group elements

Abstract

New data on both electronic and atomic structures of hydrogen bronze, H x WO 3, and a compound H x WSe 2 with a layered structure have been obtained using two methods of X-ray absorption spectroscopy — XANES and EXAFS. Information about interatomic interaction, metal–hydrogen bonds and their ionic component has been obtained by means of an investigation of positions and shapes of the L III-absorption edge of tungsten and K-absorption edge of selenium in the nearest absorption region (XANES) in WSe 2, WO 3 and H x WSe 2, H x WO 3 . A possibility of investigation of changes in the atomic-crystalline structure during transformation WO 3⇒H x WO 3 and WSe 2⇒H x WSe 2 was tested, studying changes of the extended fine structure (EXAFS) of the X-ray L III-absorption spectra of tungsten and K-absorption spectra of selenium. The analysis of spectra fine structure indicates a sensibility of the EXAFS-method concerning small atom displacements in the WO 3 and WSe 2 compounds due to hydrogen insertion.