Innershell photoionisation spectroscopy of NaCl clusters

X-ray absorption near edge spectroscopy (XANES) was used to investigate the size dependent development of XANES structures from free molecules and clu sters up to the solid NaCl. For measurements on clusters a new type of clus ter source was designed in order to provide an intense and continuous clust er beam for inner shell absorption experiments on tightly bound clusters. P artial ion yield absorption spectra at the Cl 2p-edge were recorded for dif ferent NanCln-1 ions using a time-of-flight mass spectrometer at the high f lux and high resolution undulator beamline BW3 at HASYLAB. The absorption s pectra revealed a gradual evolution from the NaCl molecule and cluster to t he solid. A comparison with recently performed multiscattering calculations indicates that the bond length even for rather small clusters (n=4) is inc reased by approximately 50% of the bond length change from the molecule to the solid. (C) 1999 Elsevier Science B.V. All rights reserved.