An ethoxy intermediate in ethanol dehydration on Brønsted acid sites in zeolite

Acid-catalyzed ethanol dehydration on zeolite is shown to proceed via a covalent ethoxy group (C2H5O) as a stable intermediate, which was directly observed by IR spectroscopy.     

Generation of infrared radiation by stimulated Raman scattering in para-hydrogen crystal at 5 K

We report the preliminary results of our experiments with stimulated Raman scattering in para-hydrogen crystal aimed at developing a continuously tunable laboratory laser source of mid-infrared radiation. With laser pulses at 532 nm, a conversion efficiency for the first Stokes beam of as much as 20% in the forward direction was observed through a single-pass, 5-cm-long crystal. Generation of mid-infrared pulses at 4.5 microm was achieved by use of the output of a near-infrared pulsed laser (1.6 microm, 3 ns), and an absorption spectrum of gaseous CD4 molecules was successfully recorded. These results suggest use of the solid para-hydrogen Raman shifter as a promising light source for mid-infrared spectroscopy.     

Influence of organic vapours on exo-electron emission from sandblasted mild steel

The influence of various organic vapours on the exo-electron glow curves for sandblasted mild steel was examined. The emission intensity of the peak which was observed at 51–66 °C in the glow curve was ranked as follows: n-butyl chloride? acetonitrile < benzene < methanol?toluene?acetone?ethanol?isopropyl alcohol< ethyl acetate? propylamines. This listing closely resembles to that of the proton attracting power of the functional groups of the organics. From this, it is supposed that the peak emission may be promoted through the formation of hydrogen bond between the functional groups and the deformed solid surface.     

Laser Spectroscopy of the CCO Radical in the 0.77-μm Region: Analysis of theÃ(020)κΠ andÃΠi(001) States

TheÃ(020)κ³Π–X³Σ⁻(000) andóΠ_i(001)–X³Σ⁻(000) bands of the CCO radical have been investigated by laser spectroscopy with two types of tunable laser system. An analysis was made simultaneously for both the bands to establish line assignments and determine molecular constants for both theÃ(020) andÃ(001) states. A coupling constant between these two states was also determined by assuming the interaction to be of Fermi type.     

Topology of zero riemann curvature flat space in supergravity

The equation of motion of the gravitino is investigated in a flat space reduced from the Kerr geometry by taking the massless limit of the gravitational source. We adopt the ansatz ψ_μ(x)=δ_μoψ(x), i.e., the Coulomb potential analogue to the Rarita-Schwinger Majorana field of the gravitino. A non-trivial exact classical solution of ψ(x) is obtained and it is interpreted as the source of the intrinsic topology of the background flat space. This flat space is spanned by two Minkowski sheets interconnected through a disk of radius a (the angular momentum parameter in the Kerr geometry).     

UV and IR absorption spectra of C3 embedded in solid para-hydrogen

This paper presents the UV and IR absorption spectroscopy of small carbon molecules of C₃ observed using a high-resolution Fourier-transform spectrometer. The C₃ molecules were produced by irradiation of dimers or larger clusters of acetylene with an ArF laser (λ=193 nm). Sharp UV absorption features with multiple structures were observed in the electronic transition of C₃. The sharp UV absorption demonstrates the potential of solid para-hydrogen as a matrix for high-resolution spectroscopy of UV–vis electronic transitions.     

Pressure control of a pressurized proportional counter for 4 pi beta-gamma coincidence counting--effects of pressure variation and study of a non-flow type system

Effects of the pressure variation of counting gas on the efficiency function were examined using a 4 pi beta-gamma coincidence counting system with a pressurized proportional counter. The results showed that the pressure variation of about ten kPa could not give large effects on the efficiency function and that a non-flow type of pressurized proportional counter with a simple gas control system could work well in the case of the pressure higher than 1 MPa, an ordinary pressure for the counting.     

Development of a Lyman-α laser system for spectroscopy and laser cooling of antihydrogen

Hydrogen Lyman-α radiation (121.56 nm) is important because it allows for the excitation and detection of ground-state hydrogen atoms by a one-photon process. The trapping of antihydrogen, recently reported by the ALPHA collaboration at CERN, has revived interest in Lyman-α lasers. In order to perform high precision tests of matter-antimatter symmetry violations or gravity-antimatter interactions with antihydrogen, laser cooling using the 1s ? 2p single photon transition is essential. Recent theoretical simulations predict that even with a pulsed Lyman-α source, laser cooling of antihydrogen would be possible. Here we describe the implementation of a high power vacuum-ultraviolet (VUV) laser at the Lyman-α transition of hydrogen. The VUV light was generated using a two-photon-resonant four-wave mixing process in a phase-matched mixture of krypton and argon. Two wavelengths (ω _R → 202.31 and ω _T → 602.56 nm) were mixed in a sum-difference scheme (ω _VUV = 2ω _R ? ω _T ) with a two-photon resonance at (4s ²4p ⁵5p[1/2]₀ ← 4s ²4p ⁶(1S ₀)) transition in Kr. With an Ar/Kr mixture of 3.9:1 we obtained 10 ns pulses of 0.1 μJ of energy at a repetition rate of 10 Hz.