Xps Study of Neutral Mixed Valence Ru Dimer: [(acac)2Ru]2(Bpz4) and Afm Study of Water Meniscus Between an Afm Tip and Nacl Substrate

This thesis consists of two parts. In the first part, X-ray photoelectron spectroscopy (XPS) was used to study a new neutral mixed valence complex: [((acac)2Ru)2B(pz)4]. XPS study of the a powder sample of the Ru dimer indicated only one group of Ru signals with binding energies close to those of RuIII in Creutz-Taube-type complexes, which suggested that the Ru dimer used was possibly oxidized RuIII/RuIII during the experiment. Surface attachment of the Ru dimer was measured on self-assembled monolayers of alkanethiols with various terminal groups. Contact angle, ellipsometry and XPS measurements suggested that the Ru dimer molecules form self-limiting monolayers on hydrophilic surfaces and not bind detectably to hydrophobic surface. Additionally, an anchoring group 4-mercaptopyrazole was studied by XPS, demonstrating that the adsorption of the molecules on gold surface is self-limiting. In the second part, water meniscus condensed between an AFM tip and a NaCl substrate was studied in various conditions, including ambient, dry nitrogen and ultra-high vacuum (UHV). Water meniscus formation was measured by probing the ability of the meniscus to dissolve the NaCl near the contact point and evaluating the pull-off point as a function of water partial pressures. These studies are consistent with the formation of water meniscus under ambient and dry conditions.