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Characterization of protonated formamide clusters by vibrational predissociation spectroscopy confirms theoretical predictions that O-protonation occurs in preference to N-protonation in formamide. Results of the work carried out suggest an interesting possibility of C-H...O bond formation in the protonated formamide trimer.

The combined techniques of vibrational predissociation spectroscopy and density functional theory calculations are used to investigate the competitive solvation of the excess proton in protonated mixed methanol and water clusters [H(super +)(CH3OH)m-(H2O)n, m+n =4]. The competitive solvation of a charge between the constituent solvent molecules within a cluster is described.

Rearrangement of hydrogen bonds in the protonated methanol-water cluster ion H(super +)(CH3OH)(sub 4)H2O is analyzed. The analysis based on ab initio calculations performed at the B3LYP/aug-cc-pVTZ/6-31 + G and MP4/6-311+G//B3LYP/6-31+G levels of computation, provides information about potential minima, transition states, and pathways for the hydrogen bond rearrangement processes.

A review of the integration of the complementry metal oxide semiconductors (CMOS) circuit with the microelectromechanical systems (MEMS) structures for sensing and RF applications has been presented. Specifically, the integrated mechanical sensors, chemical gas sensors, and biochemical sensors have been discussed. Application of MEMS as switches, varactors, and inductors and their integration in RF circuits has also been highlighted. The fabrication and design challenges for the CMOS-MEMS integration have been described. A new design methodology for integration of thermal effects in an integrated pressure sensor has been proposed. [ABSTRACT FROM AUTHOR]

Single charge transfer reactions in the collision of ions at a laboratory energy of 2 keV with N 2 were observed using translational energy spectroscopy (TES). Within the limitation of the energy analyser resolution (∼ 8/ q eV, q being the ionic charge number), the translational energy spectrum shows a single broad charge transfer peak with a rich substructure. The latter looks like a conglomeration of closely spaced channels clumped together, corresponding mainly to charge transfer into excited states , rather than into the ground state. The reaction channel assignments were made using data available in the literature. Our findings are in accord with a recent experimental result, but there are no theoretical calculations to compare our experimental measurements with. [ABSTRACT FROM AUTHOR]

Size-selected hydroxide ion water tetramers and pentamers [OH[sup -] (H[sub 2]O)[sub 4,5]], produced by a supersonic expansion, have been investigated using vibrational predissociation spectroscopy in conjunction with ab initio calculations based on density functional theory (DFT). The observed spectra in the frequency range 2650-3850cm [sup -1] show some broad absorption bands attributed to the free and hydrogen bonded OH stretches of OH[sup -] (H[sub 2]O)[sub 4,5] at an estimated cluster temperature of 170 K. DFT calculations performed at the B3LYP/6-31+ G* level reveal five and eight possible low lying isomeric forms for OH[sup -] (H[sub 2]O)[sub 4] and OH (H[sub 2]O)[sub 5], respectively. The global minimum isomer of the tetramer is tri-solvated cyclic, which is energetically more stable than the tetra-solvated wheel-shaped form with an OH ion at its centre. Compact cage-like lowest energy structures are found for the pentamer, in which the water molecules can act either as a single-donor-single-acceptor, as a double-proton-donor, or as a double-donor-single-acceptor in both the first and the second solvation shell of the OH ion core. Interconversion among the isomers appears to be rapid as manifested in the observed spectra dominated by broad and congested absorptions. To understand the nature of spectral broadening and congestion, systemic comparisons of the results are made against those of the corresponding protonated cations, H[sup +](H[sub 2]O)[sub n+1] and the corresponding halide anions, X[sup -] (H[sub 2]O)[sub n], X = F, Cl, Br, and I. It is suggested that the spectral complexities observed for OH[sup -](H[sub 2]O)[sub 4,5] are predominantly a result of sampling configurations with a large distribution of O[sub solvent]-O[sub ion]-O[sub solvent] angles and O[sub solvent] · · · H-O[sub solvent] distances between water molecules in the first and/or second hydration shells, together with the existence of more than one isomer in the supersonic expanson and rapid isomeric interconversion among them. [ABSTRACT FROM AUTHOR]