Simultaneous measurements of solid-liquid interfaces and bulk liquids using soft X-ray absorption spectroscopy

Simultaneous measurement methods for soft X-ray absorption spectroscopy (XAS) of solid-liquid interfaces and bulk liquids have been developed. The O K-edge XAS spectra of H₂O/Au interfaces and bulk H₂O were measured using a transmission-type liquid cell, in which the liquid layer was sandwiched between Au/Cr/Si₃N₄ and Si₃N₄ membranes. The XAS spectrum of bulk H₂O was obtained using the transmission method by controlling the thickness of the liquid layer, whereas the XAS spectrum of the H₂O/Au interface was obtained using the electron-yield method by measuring the drain currents from the Au surface after soft X-ray absorption. The XAS spectra of bulk H₂O and the H₂O/Au interfaces were differentiated to determine the appropriate measurement conditions for the solid-liquid interfaces interfaces.