The stationary Schrödinger equation with continuum boundary conditions is solved numerically. Quantum probabilities of collision-induced dissociation/recombination for models with two degrees of freedom are calculated using an integral-equation matching procedure together with analytical wavefunctions or finite element solutions alternatively. Model results for He+Ne2 → He+2Ne are reported. 相似文献
Novel organometallic uranium(IV) complexes of the composition [(η5-Cp)3UIV]2[MnII(CN)4] Cp = C5H5, M = Ni or Pt) have been prepared from Cp3UCl and K2[M(CN)4] in aqueous solution. On the basis of their properties they are characterized as layered oligomeric structures involving squared arrays of both the U and M atoms within the same plane, and a presumably trigonal bipyramidal coordination of the uranium(IV) ion. 相似文献
A number of mixed ligand complexes of the type [Co(en)2(Im)Cl]Cl2 (Im = imidazole or a substituted imidazole) have been synthesized by reaction of trans-[Co(en2Cl2]Cl with the imidazole ligands. Electrical conductivity measurements support the ionic (1:2) formulation of the compounds, the electronic spectra is in agreement with an octahedral stereochemistry, and the IR and NMR (1H and 13C) spectra strongly favour the cis configuration for the isolated complexes, [Co(en)2(Im)Cl]Cl2.Trans-[Co(en)2Cl2]Cl reacts with KNCS to form cis-[Co(en)2(NCS)2Cl, the crystal structure of which is briefly reported. This lends additional support in favour of the probable cis configuration of the above complexes. 相似文献
We have calculated the spherical v0 and anisotropic radial components v2 and v4 in the usual Legendre expansion for the rigid rotor He-N2 potential using the method of Tang and Toennies Potential curves covering the range of internuclear distances from 2.5 to 8.0 Å, which includes the minimum region, arc presented and compared with a recent experimental potential derived from differential total cross sections. 相似文献
The tetravinyltin molecule has been studied by gas phase electron diffraction. The ra structure analysis is based on the assumptions that a single conformer occurs in Sn(CHCH2)4 and that tin has a tetrahedral bond configuration. The preferred model (S4 symmetry) predicts all four vinyl groups to be intermediate between staggered and eclipsed conformations. The structure refinement gives the following parameters (bond lengths, ra, in nm, valence angles in degrees):, SnCC = 121.9(0.6), CC = 0.1349(8), SnCH = 116.8(4.5),<C—H?av. = 0.1098(14). The uncertainties given in parentheses represent three times the standard deviation values.The observed shortening of the bond in Sn(CHCH2)4 from in SnMe4 (by 0.0027 nm) is equal to the shortening that occurs on going from in ethane to in propylene. With the corresponding Si and Ge derivatives, this effect is less pronounced. 相似文献
The torch and nebulizer of an existing argon ICP system were modified and the system was (re-) optimized for aqueous and organic liquids. The paper describes the design considerations and construction of(1) a new, streamlined torch including a torch base used in this study, where a demountable rather than a prealigned version of the torch was preferred;(2) a cross-flow pneumatic nebulizer with adjustable teflon capillaries including a spray chamber with flow spoiler, concentric aerosol pick-up tube, and “U” tube with unequal legs to smooth the flow of wasted liquid to the drain.The (re)-optimization of the ICP system for analysis of aqueous solutions with inorganic matter or with both inorganic and organic matter is discussed in the light of earlier work in this laboratory regarding the selection of “compromise conditions” and the choice of representative spectral lines and measurement criteria for establishing such compromise conditions. In this context the authors consider the concepts of norm temperature and “hard” and “soft” lines, as well as recent results of measurements of spatial distributions in ICPs. The authors further describe experiments aimed at the optimization of the operating conditions of an “organic ICP” using methyl isobutyl ketone (MIBK) as organic solvent. Trends of net line and background signals and signal-to-background ratios with the ICP parameters (power; outer, intermediate and carrier gas flow; observation height; liquid feed rate) are reported, and a rational choice of compromise conditions for the ICP is argued.Performance characteristics of the modified ICP system, such as detection limits, precision and interference level, achieved under compromise conditions, have been communicated in a previous report [Spectrochim. Acta36B, 1031 (1981)] to demonstrate the capabilities of the system for analysis of aqueous solutions. Detection limits in MIBK and oil diluted in MIBK are reported in the present work as an illustration of the performance of the system when used for organic liquid analysis. 相似文献
A series of methylcyclosiloxanes from the trimer to the hexamer has been investigated by gas phase electron diffraction. The Si-O bond distance varies between 1.635 and 1.620 Å, the SiOSi angle has values from 132° to 149° within the series. The trimer is substantially planar, the best agreement for the tetramer was obtained with a model of S4. symmetry. As a consequence of large amplitude vibrations, the larger rings do not possess a well-defined conformation. The results are discussed in relation to previous spectroscopic investigations. 相似文献
Fluorescence lifetimes and fluorescence quenching rates are reported for several vibronic levels in the A2Πu electronic manifold of BO2. The relationship of these results to earlier Hanle-effect measurements is discussed. 相似文献
The energies of the low lying electronic states of p-cyano-N,N-dimethylaniline (CDMA) in its planar and in 90° twisted conformation have been calculated using the modified INDO method. Solvent effects have been taken into account. The results agree reasonably well with the experimental data and support the hypothesis of the dual fluorescence of CDMA as being related to the intramolecular rotation of the N(CH3)2 group, with a decisive role of the solvent polarity. 相似文献
A number of mixed ligand complexes, nitro(imidazole) bis(acetylacetonato) cobaltate(III), [Co(acac)2 (NO2 )2 (L)] (L = imidazole or substituted imidazole) have been synthesised and characterised on the basis of chemical analyses, IR, electronic, mass and nuclear (1H and 13C) magnetic resonance spectra as well as TGA and DTA data. All complexes are non-electrolytic and possess a trans octahedral structure. The NO2? group is coordinated through the N atom. Though the 1H NMR data of fresh CDCl3 solutions of complexes confirm the trans structure, slow isomerisation to the cis configuration is observed at room temperature. 相似文献
The conformational structures of cis- and trans-azobenzene and benzylideneaniline have been investigated by means of ab initio SCF calculations. Contrary to semiempirical results, the equilibrium molecular geometries are correctly accounted for in the non-empirical SCF-formalism. Trans-azobenzene is found to be planar, or at least peri-planar, while the phenyl rings of the cis-isomer are twisted by 56° out-of-plane. Both isomers of benzylideneaniline are non-planar, with rotational angles θ1 (C-N) = 48°, θ2(C-C) = 0° and θ1 = θ2 = 75° for the trans and cis form, respectively. Trans-azobenzene is calculated to be more stable by 10.4 kcal mol?1 than the cis isomer, which is in good accord with the experimental value of 10 kcal mol?1. The energy of isomerization of benzylideneaniline amounts to 13.0 kcal mol?1. 相似文献
Using 298 and 160(3) K diffractometer intensity data the structure of Rb2TeBr6 has been determined by single crystal X-ray technique and refined to a final Rw of 0.041 and 0.037, respectively (K2PtCl6 type structure, space group Fm3m, Z = 4 with a298 = 10.773(4) Å and a160 = 10.713(6) Å). The powder diffraction pattern from 300 to 12.5 K was recorded by a low-temperature Guinier diffractometer and camera. Below 45(5) K a second-order phase transition leads to a tetragonally distorted structure corresponding to a softening of the T1g(Γ) rotary phonon. The powder pattern measured with the diffractometer at 12.5 K was used for structural refinement (R = 0.092). This low-temperature phase shows a ferrorotative displacement of the TeBr6-octahedra with a tilt angle of 4.7(1) deg. (space group Å and c = 10.7008(5) Å). The structural results indicate that there is no stereochemical activity of the lone pair electrons at Te(IV) even at very low temperatures. Phase transitions of Rb2TeBr6 and Rb2TeI6 (A2g(X)-condensation) are compared. The results of a lattice dynamic calculation shows that only the T1g(Γ) condensation can be explained with a rigid ion model. 相似文献
A variety of partially chlorinated and deuterated phenalenyl radicals has been produced by the reaction of the respective acenaphthylenes with chloroform as a carbenoid precursor and via thermal decomposition of some mercury carboxylates. By ESR and ENDOR-in-solution measurements the effectiveness of the different reaction paths to specifically substituted compounds has been investigated. 相似文献
The adsorption properties of copper(II) sulfide in various acid solutions for different radiotracers are described. Column and batch equilibration methods are discussed. Copper(II) is selectively adsorbed on CuS; the decontamination factor exceeds 106 for column operations in 6 M hydrochloric acid solution. Among the 30 ions tested in 6 M hydrochloric acid, only copper and gold are adsorbed quantitatively; mercury, silver, bromine, technetium and molybdenum are adsorbed partially. The retention capacity for copper(II) is around 20 mg Cu/g CuS. The adsorption processes on CuS as functions of acid concentrations (HCl, HClO4 and H2SO4) are described. The method seems applicable in activation analysis for trace elements in copper matrices. 相似文献
The conditions for the reaction between phenylarsenazo (PAA) (2-[(2-arsonophenyl)azoj-7-(phenylazo)-1, 8-dihydroxynaphthalene-3,6-disulphonic acid) and chromium(III) have been studied. A blue 1:1 complex is formed at pH 2.2 on heating the reactants at 100 degrees for 15 min. It has maximum absorption at 635 nm and is stable for at least 24 hr. The molar absorptivity is 3.3 x 10(4) 1.mole(-1).cm(-1). Beer's law is obeyed in the chromium concentration range 0-1.4 mug ml . The reaction has been successfully applied to determination of chromium in alloy steel. 相似文献
The crystal structure of bicyclo [3.3.3]undecane-1,5-diol has been determined. It is monoclinic, P21/c, a = 12.99(2), b = 14.16(2), c = 12.50(1)A,β = 112.42(2)°, with two independent molecules in the asymmetric unit. One of these is disordered, but the other has almost exact C3h symmetry and its conformation and precise molecular geometry agree well with previous calculations by molecular mechanics. The molecule shows considerable angle strain, having bridge angles in the range 118–121° 相似文献
Results from steady-state and transient photokinetic and spectroscopic measurements, show the formation in aqueous solution of a triple radiative exciplex between excited UO2+2 and TI+. Rate constants of exciplex formation and deactivation are evaluated The nature of bonding and the emittive properties of this species, of probable 1(Tl·OUO-Tl)4+ structure, are discussed. 相似文献
The 13C chemical shifts, the 13C31P coupling constants, and some one-bond 13C1H coupling constants were measured for the title compounds. For the ylides of phosphorus, arsenic and sulfur, the data are consistent with an sp2-hybridized ylidic carbon with a strong, localized negative charge, while for the pyridinium ylide this charge is much more delocalized. in the homologous series of salts the electron-withdrawing ability of the groups studied varies in the order: Ph3P+ < Ph3As+ « Me2S+ « Me2C5H3N+. The differences in the carbonyl chemical shift between the ylides and the corresponding salts are a measure of the resonance stabilization of the negative charge in the form X+CCO?; this stabilization varies with the groups studied in the order: Ph3P+ < Ph3As+ ≈ Me2S+ « Me2C5H3N+. The ylide—palladium(II) complexes contain a bond between the ylidic carbon and the metal: the ylidic carbon is shifted upfield in the complex with respect to the free ligand, while the adjacent carbonyl is shifted strongly downfield. These data suggest that the PdC(1) bond is strongly polarized with a high electron density on the C(1) atom which cannot be delocalized through resonance as in the free ligands. 相似文献