Vacuum ultraviolet and soft X-ray photoelectron spectroscopy of liquid beams using a hemispherical photoelectron spectrometer with a multistage differential pumping system

We present photoelectron spectroscopy of liquid beams using a high-resolution hemispherical photoelectron spectrometer with a multistage differential pumping system developed in our laboratory. Intense soft X-ray synchrotron radiation (500-1200 eV) at SPring-8 and a relatively large detection solid angle (1.5 × 10^-2 π sr) of the spectrometer enable highly efficient measurements of X-ray photoelectron spectra of liquids. Vacuum ultraviolet photoelectron spectroscopy using the same spectrometer provides sufficiently high spectral resolution to resolve rotational isomers of gas-phase molecules.