Isomorphic electron orbitals for vibronic flexibility in a cyclopropenyl radical molecular device

Summary The vibronic character of this molecular device has been studied using isomorphic electron orbitals. The leading role of the softest vibrational mode for the electron transport process is stressed by the quantum mechanical treatment of the rearrangement operator. The theory was used to investigate the possible function of the soliton valve, which has been suggested as a switching tip. The electronic flexibility of the cyclopropenyl radical with respect to molecular vibrations, which is important for the function of the molecular device, is well characterized by the hardness and softness of the electron structure in terms of the orbital energy-occupation number correlation diagram.     

The study of electron beam flue gas treatment for coal-fired thermal plant in Japan

The fundamental research work with simulated coal-fired flue gas was performed in JAERI to get basic data for electron beam treatment of flue gas from thermal power plants in Japan. The standard condition of the experiments was set to be the same as that of next large scale pilot test in Nagoya. The concentrations of NO_x and SO_x were 225 ppm and 800 ppm, respectively. The temperature of the system was 65°C. The effect of multiple irradiation was observed for NO_x removal. The target SO_x and NO_x removals (94% and 80%, respectively) with low NH₃ leakage (less than 10 ppm) were achieved at 9 kGy irradiation with 0.9 NH₃ stoichiometry during 7 hours continuous operation. The facility for the pilot plant (12,000 Nm³/hr) has just built at the site of Shin-Nagoya power plant of Chubu Electric Power Company and will be started in full operation in November 1992.     

Use of cluster expansion techniques in quantum chemistry. A linear response model for calculating energy differences

In this paper we have reviewed the theoretical framework of the coupled-cluster (cc) based linear response model as a tool for directly calculating energy differences of spectroscopic interest like excitation energy (ee), ionisation potential (ip) or electron affinity (ea). In this model, the ground state of a many-electron system is described as in a coupled cluster theory for closed shells. The electronic ground state is supposed to interact with an external photon field of frequencyw, and the poles of the linear response function as a function ofw furnish with the elementary excitations of the system. Depending on the general form of the coupling term chosen, appropriate difference energies like ee, ip or EA may be generated. Pertinent derivations of the general working equations are reviewed, and specific details as well as approximations for ee, ip or ea are indicated. It is shown that the theory bears a close resemblance to the equation of motion (eom) method but is superior to the latter in that the ground state correlation is taken to all orders and may be looked upon as essentially a variant of renormalisedtda. A perturbative analysis elucidating the underlying perturbative structure of the formulation is also given which reveals that the theory has a hybrid structure: the correlation terms are treated akin to an open shellmbpt, while the relaxation terms are treated akin to a Green function theory. A critique of the methodvis-a-vis other cc-based approaches for difference energies forms the concluding part of our review.     

Structure and energy studies of β-diketonates. XIII. Molecular structure of gadolinium tris-hexafluoroacetylacetonate Gd(C5O2HF6)3

In a mass spectrometric study, it was found that the saturated vapor over gadolinium tris-hexafluoroacetylacetonate Gd(C₅O₂HF₆)₃ contains molecular forms with a mass exceeding the mass of the dimer. The vapor overheated to 250–300°C contains only the monomer form. Simultaneous electron diffraction and mass spectrometric experiment aimed at investigating the structure of the Gd(hfa)₃ monomer molecule was carried out at 284(5)°C. The Gd(hfa)₃ molecule was found to have the symmetry of the equilibrium D ₃ configuration. The basic structural parameters are r _h1(Gd-O) = 2.291(10) Å, r _h1(O-C) = 1.257(10) Å, r _h1(C-C_r) = 1.404(6) Å, r _h1(C_F-F)_av = 1.341(3) Å, ∠OGdO = 72.8(0.4)°. The GdO₆ coordination polyhedron has the structure of a distorted antiprism. The rotation angle of the O-O-O trigonal faces relative to their position in a regular prism is 18.7(0.9)°. Quantum chemical calculations (HF/SBK, 6-31G*) generally reproduce the experimental structure, but the Gd-O internuclear distance is exaggerated by 0.04 Å.     

Dynamic study of photosensitized one-electron oxidation of polyG by menadione

Quinones including menadione are ubiquitous in nature. They play important roles in aerobic respira- tion and photosynthesis[1,2]. In addition, exogenous quinones are used as antibiotics and anticancer drugs. Their function is closely related to their red…     

Condensation of 4-aryl-4-oxobutanoic acids with benzylamines: Synthetic and structural studies on 1-arylmethyl-3-[(<Emphasis Type="Italic">E</Emphasis>)-1-arylmethylidene]-5-phenyl-2,3-dihydro-1H-2-pyrrolones

The microwave-mediated reaction of 4-aryl-4-oxobutanoic acids with benzylamines furnished 1-arylmethyl-3-[(E)-1-arylmethylidene]-5-phenyl-2,3-dihydro-1H-pyrrolones. This result is in contract to the earlier report on this reaction conducted under neat conditions. Structures for the products were assigned on the basis of spectral data and confirmed by independent synthesis. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 368–373, March, 2007.     

PREPARATION OF POLY（METHYL METHACRYLATE）/LAYERED DOUBLE HYDROXIDES NANOCOMPOSITES via in situ SOLUTION POLYMERIZATION

An exfoliated layered double hydroxides/poly(methyl methacrylate)(LDHs/PMMA)nanocomposite was prepared by in situ solution polymerization of methyl methacrylate(MMA)in the presence of 4-vinylbenzenesulfonate intercalated LDHs(MgAl-VBS LDHs).MgAl-VBS LDHs was prepared by the ion exchange method,and the structure and composition of the MgA1-VBS LDHs were determined by X-ray diffraction(XRD),infrared spectroscopy and elemental analysis.XRD and transmission electron microscopy(TEM)were employed to examine the structure of LDHs/PMMA nanocomposite.It was indicated that the LDHs layers were well exfoliated and dispersed in the PMMA matrix.The grafting of PMMA onto LDHs was confirmed by the extraction result and the weight fraction of grafted PMMA increased as the weight fraction of LDHs in the nanocomposites increased.     

Microwave and RF surface wave sustained discharges as plasma sources for plasma chemistry and plasma processing

The surface wave produced plasma belongs to a class of RF and microwave induced plasmas. It results from the propagation of an electromagnetic wave which uses the plasma column it sustains and the plasma tube as its sole propagating media. This type of plasma offers several advantages compared to the positive column plasma of dc discharges or to other RF and microwave produced plasmas. Surface wave plasmas require no internal electrodes, and they can be applied over an extremely broad range of wave frequencies (27 MHz to 10 GHz demonstrated) and gas pressures (about 10^–4 Torr to a few times the atmospheric pressures). Using the surface wave plasma technique, a large variety of plasma column diameters have been created (0.5–150 mm demonstrated) and no limitation on plasma column length (column up to 6 m long demonstrated) has been found. The surface wave produced plasma is used in elemental analysis and to sustain emission in lasing media. This article is intended as a guide for potential users of surface wave plasmas in the field of plasma processing and plasma chemistry.     

Air microwave-induced plasma: Relation between ion density and atomic oxygen density

Electron temperature and ion density are measured in an air microwave-induced plasma (2450 MHz) by means of a floating double probe. A 'cinetic scheme for ion formation and decay is set up, and a relationship between atomic oxygen and ion densities is obtained. From this relationship an order-of-magnitude of atomic oxygen concentration in the discharge is derived and compared with results obtained by optical actinometry in another work.     

Unexpected formation of the novel fluorinated diazenes

Fluoroalkanesulfonyl azides reacted with morpholine giving unexpectedly N-fluoroalkanesulfonyl-N-morpholino diazenes, which were fully characterized by using spectral methods and X-ray diffraction analysis.