We report the first measurement of water monomer bending vibrations in gaseous (H2O) n clusters. Infrared cavity ringdown spectroscopy reveals discrete and sequentially blue-shifted bands near 6 μm for n = 2−4 and unresolved broad features for n > 4, supporting both theoretical predictions and solid-state spectroscopy results. These measurements provide a measure of the monomer distortion that accompanies sequential hydrogen bond formation, which will be valuable for the construction of potential energy surfaces for describing water.

Since the first report of ultraviolet lasing from ZnO nanowires, [1] substantial effort has been devoted to the development of synthetic methodologies for one-dimensional ZnO nanostructures. Among the various techniques described in the literature, evaporation and condensation processes are favored for their simplicity and high-quality products, but these gas-phase approaches generally require economically prohibitive temperatures of 800-900 8C.[2] Despite recent MOCVD schemes that reduced the deposition temperature to 450 8C by using organometallic zinc precursors, [3] the commercial potential of gas-phase-grown ZnO nanowires remains constrained by the expensive and/or insulating (for example, Al 2 O 3 ) substrates required for oriented growth, as well as the size and cost of the vapor deposition systems. A low-temperature, large-scale, and versatile synthetic process is needed before ZnO nanowire arrays find realistic applications in solar energy conversion, light emission, and other promising areas.Solution approaches to ZnO nanowires are appealing because of their low growth temperatures and good potential for scale-up. In this regard, Vayssieres et al. developed a hydrothermal process for producing arrays of ZnO microrods and nanorods on conducting glass substrates at 95 8C. [4,5] Recently, a seeded growth process was used to make helical ZnO rods and columns at a similar temperature.[6] Here we expand on these synthetic methods to produce homogeneous and dense arrays of ZnO nanowires that can be grown on arbitrary substrates under mild aqueous conditions. We present data for arrays on four-inch (ca. 10 cm) silicon wafers and two-inch plastic substrates, which demonstrate the ease of commercial scale-up. The simple two-step procedure yields oriented nanowire films with the largest surface area yet reported for nanowire arrays. The growth process ensures that a majority of the nanowires in the array are in direct contact with the substrate and provide a continuous pathway for carrier transport, an important feature for future electronic devices based on these materials.Well-aligned ZnO nanowire arrays were grown using a simple two-step process. In the first step, ZnO nanocrystals (5-10 nm in diameter) were spin-cast several times onto a four-inch Si(100) wafer to form a 50-200-nm thick film of crystal seeds. Between coatings, the wafer was annealed at 150 8C to ensure particle adhesion to the wafer surface. The ZnO nanocrystals were prepared according to the method of Pacholski. [7] A NaOH solution in methanol (0.03 m) was added slowly to a solution of zinc acetate dihydrate (0.01m) in methanol at 60 8C and stirred for two hours. The resulting nanoparticles are spherical and stable for at least two weeks in solution. After uniformly coating the silicon wafer with ZnO nanocrystals, hydrothermal ZnO growth was carried out by suspending the wafer upside-down in an open crystallizing dish filled with an aqueous solution of zinc nitrate hydrate (0.025 m) and methenamine or diethylenetriamine (0.025 m) at 90 8C. R...

Fully coupled 6D calculations of the ammonia vibration-inversion-tunneling states with a split Hamiltonian pseudospectral approach J. Chem. Phys. 111, 7236 (1999); 10.1063/1.480099Six-dimensional quantum calculation of the intermolecular bound states for water dimer Fully coupled six-dimensional calculations of the water dimer vibration-rotation-tunneling states with a split Wigner pseudo spectral approachThe SWPS method is improved by the addition of H.E.G. contractions for generating a more compact basis. An error in the definition of the internal fragment axis system used in our previous calculation is described and corrected. Fully coupled 6D ͑rigid monomers͒ VRT states are computed for several new water dimer potential surfaces and compared with experiment and our earlier SWPS results. This work sets the stage for refinement of such potential surfaces via regression analysis of VRT spectroscopic data.

We present the results of laser magnetic resonance measurements performed on the ground 2 P state of singly ionized atomic carbon (C II). The 2 P 312 +-2 P 112 fine-structure intervals of both 12~+ and 13 C+ ha~e been determined with a precision of approximately 1 ppm, and the gJ factors to approXImately one part m 10 4 • Specifically, we find that gJ= 1 ; 2 = 0.66576(11) and gJ= 3; 2 = 1.33412(11), while for 12 C+ !lEoeP3!2 +-2 P1;2) = 1900536.9(1.3) MHz, with !lE 0 eP 312 +-2 Pl/ 2) = 1900545.8(2.1) and !lEeP312 +-2 P~/2• F= 2 ~ 1) = 1900466.1(2.3) MHz in 13 C+. The highly precise values of the 12 C II and 13 C II fine-structure mtervals venfy the already secure far-infrared astronomical identification of C + and should allow the interstellar 12 C / 13 C ratio to be unambiguously determined in a number of environments.