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Discusses thick film resistors as an alternative to thin-film platinum temperature sensors. Resistance and resistivity; Transmission electron microscopy characterization; Microscopic composition and crystallography; Role of morphology on temperature coefficient resistance.

Examines the effect of lattice stress relaxation on the microstructures of epitaxial thin films by domain structure studies of epitaxial SrRuO thin films grown on vicinal SrTiO substrates. Experimental procedures; Results and discussion; Conclusion.

Investigates the clustering of water on protonated molecular ions by vibrational predissociation spectroscopy. Resemblance of the hydroxide stretch spectra in the protonated ion-water clusters; Supersonic expansion of the ions to establish complexation with water.

Cluster isomers of H[sup +](CH[sub 3]OH)[sub 4]H[sub 2]O have been identified by vibrational predissociation spectroscopy in combination with mass-selected detection of photofragments. Ab initio calculations indicate that the cluster ion can exist in either CH[sub 3]OH[sub 2][sup +](CH[sub 3]OH)[sub 3]H[sub 2]O or H[sub 3]O[sup +](CH[sub 3]OH)[sub 4] isomeric forms. They can dissociate via a methanol loss or water loss channel, depending on the structure of the isomers. While water loss is the dominant channel of the dissociation, the methanol loss channel is readily accessible by the H[sub 3]O[sup +]-centered cluster isomer. We demonstrate in this study that mass-selected detection of photofragments produced by vibrational excitation is an effective way of identifying cluster isomers in the gas phase. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Behaviors of an excess proton in solute-containing water clusters were investigated using infrared spectroscopy and ab initio calculations. This investigation characterized the structures of protonated methanol-water clusters, H[sup +](CH[sub 3]OH)(H[sub 2]O)[sub n] with n=2-6, according to their nonhydrogen-bonded and hydrogen-bonded OH stretches in the frequency range of 2700-3900 cm-1. Ab initio calculations indicated that the excess proton in these clusters can be either localized at a site closer to methanol, forming a methyloxonium ion core (CH[sub 3]OH[sub 2][sup +]), or at a site closer to water, forming a hydronium ion core (H[sub 3]O[sup +]). Infrared spectroscopic measurements verified the calculations and provided compelling evidence for the coexistence of two distinct structural isomers, CH[sub 3]OH[sub 2][sup +](H[sub 2]O)[sub 3] and H[sub 3]O[sup +](CH[sub 3]OH)(H[sub 2]O)[sub 2], in a supersonic expansion. The spectral signatures of them (either CH[sub 3]OH[sub 2][sup +] or H[sub 3]O[sup +] centered) are the free-OH stretching absorption band at 3706 cm-1 of a single-acceptor-single-donor H[sub 2]O, and the band at 3673 cm-1 of a single-acceptor CH[sub 3]OH. At n=4-6, the clusters adopt structures similar to their pure water analogs with five-membered rings starting to form at n=5. The position of the excess proton in them varies sensitively with the number of solvent water molecules as well as the geometry of the clusters. To further elucidate the behaviors of the excess proton in these clusters, we analyze in detail the potential energy surface along the proton transfer coordinate for two specific isomers of n=2 and 4: MW2II and MW4I. It is found that the proton can be nearly equally shared by methanol and the water dimer subunit in the form of CH[sub 3]OH-H[sup +]-(H[sub 2]O)[sub 2], as substantiated by hydrogen bond cooperativity and zero-point vibrational effects. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]