Structure of bis(4-Methyl Pyridine) Cadmium Tetracyanonickelate

Abstract

The structure, C₁₆H₁₄CdN₆Ni, consist of corrugated polymeric networks made up of tetracyanonickelate ions coordinated to Cd. The 4-methyl pyridine molecules bound to Cd in trans positions are located on both sides of the network. The bonding in the networks occurs because of a departure of the Ni-C-N-Cd sequence of atoms from linearity at the C and N positions. The crystal structure of the title compound was determined as monoclinic by single crystal X-Ray diffraction technique. The crystal parameters of this compound are as follows: monoclinic C2/m, a=18.156(2) Å, b=7.581(2) Å. c= 6.983(2) Å, β = 110.09(2)°, V = 902.6(5) ų Z=2, Dx = 1.698 g/cm³, F(000) - 456, λ (MoKα) = 0.71070 Å, μ = 2.121 mm^?1. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.02 for 1074 observed reflections with I > 2[sgrave] (I).     

Determination of the isotope shift in theD 1 line between197Au and195Au

The isotope shift between¹⁹⁷Au (stable) and¹⁹⁵Au (T _1/2=183 d) was determined by resonance fluorescence and polarization spectroscopy in the 6s² S _1/2 -6p ² P _1/2, λ =267.6nm line. The result is δν^{195, 197}=-2.9(2) GHz corresponding to a change of the mean-square charge radius by δ〈r ²〉^{195, 197}=0.063(9) fm². The sample was confined to a resonance cell heated to temperatures of up to 1500°C.     

Intense interactions of molecules with a short-wavelength electromagnetic radiation field: II. Resonance scattering of radiation and fluorescence

Within the framework of the nonadiabatic approach developed in the preceding paper, the resonance scattering, resonance Raman scattering, and resonance fluorescence are studied in detail for diatomic and triatomic molecules, and polyatomic symmetric and antisymmetric top molecules, which interact with the field of short-wavelength radiation with a wavelength λ ≥ Å and an intensity up to 10¹⁴ W/cm². The coherent excitations of high-lying Rydberg and autoionizing states are taken into account. Analytical expressions for calculating the tensors and cross sections of the above processes are derived.     

Influence of the boundary layer of a shock-heated plasma on the stark profiles of the A1(I) resonance lines

The influence of temperature and density gradients in the boundary layer of an Al(CH₃)₃-seeded shock-heated plasma on the Stark profiles of the A1(I) resonance lines λ = 3961.5 Å and λ = 3944 Å is investigated by solving the radiative transfer equation. The thermal boundary layer thickness δ is varied from 0 to 1 cm, assuming complete local thermodynamic equilibrium (LTE) throughout the inhomogeneous region. The calculations show that the line profiles are distorted. For the plasma conditions of an experiment made recently by one of us, it is shown that reabsorption diminishes the intensity and displaces the maxima of the profiles of both resonance lines in the same relative proportions. Thus, the ratios of their half-widths and of their shifts are practically independent of the boundary-layer effect. We conclude, therefore, that the measured difference of the half-widths of the A1(I) resonance doublet must be an intrinsic plasma effect.     

Structure of 4,4′-butane-(1,4,7-three-p-tolylsulphonyl-1,4,7-three amine) diphthalonitrile

Abstract

The crystal structure of the title compound, C₄₁ H₃₅ N₇ O₆ S₃ was determined as monoclinic by single crystal X-Ray diffraction technique. The molecular structure was identified by IR, ¹H-NMR, ¹³C-NMR and elemental analysis. The crystal parameters of this compound are as follows: monoclinic P 2 1/n, a = 12.694(2) Å, b = 26.204(2) Å, c = 13.005(2) Å, β = 102.95(2)°, V = 4216.02(1) Å.³, Z = 4, Dx = 1.289 g/cm³, F(000) = 1704, λ (MoKα) = 0.71070 Å, μ = 0.2 mm^?1. The structure was solved by SHELXS-97 and refined by SHELXL-97. R = 0.06 for 3178 observed reflections with I > 2σ (I).     

Structure of Quinoline-4-Carboxaldehyde-2,4-Dinitrophenyl-N Methylhydrazone

Abstract

The crystal structure of the title compound, C₁₇H₁₃N₅O₄, has been determined by single crystal x-ray diffraction at room temperature. The molecule is not planar, with dihedral angles of 7.2(1)° between the quinoline ring and N-methylhydrazone group, and 17.45(2)° between the N-methylhydrazone group and the phenyl ring. The crystal parameters of this compound are as follows: monoclinic P 21/n, a=9.525(2)Å, b = 15.192(2) Å, c = 11.302(2) A, β = 94.722(3)°, V = 1629.8(6) ų, Z = 4, Dx = 1.432 g/cm³, F(000) = 728, λ (MoKα) = 0.71070 Å, μ = 0.106 mm^?1, R_int = 0.017. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.07 for 2438 observed reflections with I > 2σ (I).     

Ultra-violet bands of mercury iodide

The ultraviolet bands of mercury iodide have been excited in uncondensed discharge and photographed with a quartz Littrow spectrograph. The bands in the region λ 2658 to 2530 Å have been analysed into two systems which may form the two components of a²Π-²∑ electronic transition with a²Π interval equal to 858·9 cm^?1. These systems and the systems in the region λ 3095 to 2647 Å have the same lower state.     

Structure of 5-Allyl-2-hydroxy-3-methoxyazobenzene

Abstract

5-allyl-2-hydroxy-3-methoxyazobenzene was preperad by the reaction of 4-allyl-2-methoxyfenol and benzenediazoniumchloride and crystallized from dimethylsulphoxide to yield crystals suitable for analysis. The molecular structure was identified by UV-VIS, IR, ¹H-NMR, ¹³C-NMR and elemental analysis. The crystal structure of the title compound was determined as monoclinic by by single crystal X-Ray diffraction technique. The crystal parameters of this compound are as follows: monoclinic P 2 1/n, a=5.559(2) Å,b=14.900(2) Å, c= 17.573(29 Å, P = 98.58(1)?, V = 1439.3(2) ų, Z = 2, Dx = 0.610 g/cm³, F(OOO) = 284, λ (MoKα) = 0.71070 Å, μ = 0.041 mm^?1. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.09 for 1107 observed reflections with I > 2σ (I).     

A general local-mode theory for high energy polyatomic overtone spectra and application to dichloromethane

A new model is developed to describe the overtone spectra of polyatomic molecules containing XH_n moieties. The infrared absorption is described as corresponding to excitation of localized modes of vibration rather than a set of symmetry allowed combinations of anharmonic normal modes. The possibility of assigning new bands in the more complex regions of the overtone spectra which involve combinations of both stretching and bending modes is examined and illustrated using the overtone spectrum of ammonia. The overtone spectrum of dichloromethane is recorded in the range λ = 9260 Å to λ = 5300 Å, and the CH overtone bands at 8850 Å, 7223 Å, and 6165 Å corresponding to the Δv_CH = 4, 5, and 6 overtones are identified. Specific features of these bands are discussed in detail in relation to the model. The common features and simplicity of the Δv_CH = 4 overtone bands of a series of halomethanes and ethanes are also interpreted in terms of the model.     

Absolute photoabsorption cross sections for H2O and D2O from λ 180–790 Å

Absolute photoabsorption cross sections for H₂O and D₂O have been measured photoelectrically from λλ 180 to 790 Å using synchrotron radiation. The cross sections increase smoothly with wavelength to ～λ610 Å, with both H₂O and D₂O displaying a broad absorption band extending above a nearly linear background from λλ 400 to 490 Å. The continuum has a maximum of ～ 22.5 Mb at λ 640 Å. Above λ 615 Å, superimposed on the continuum, a diffuse structure appears which is similar to the vibrational structure of the ²B₂ states of H₂O⁺ and D₂O⁺ as observed in photoelectron spectra. The structure is believed to arise from excitation of a 1b₂ electron to the vibrational levels of a Rydberg orbital with n¹ ≈ 2.64.     

Intense interactions of molecules with a short-wavelength electromagnetic radiation field: I. The fundamentals of the nonadiabatic theory

The intense interactions between short-wavelength (SW) electromagnetic radiation with a wavelength λ ≥ 1 Å and intensity up to 10¹⁴ W/cm² and simple and polyatomic molecules are studied with the coherent excitations of high-lying Rydberg and autoionizing states taken into account. The Hamiltonian of a system “molecule + SW radiation” is obtained by using the methods of quantum electrodynamics. Conditions for the applicability of the dipole approximation to describe the interactions of molecules with radiation of the UV, VUV, XUV, and soft X-ray range are found. The fundamentals of the theory of resonance scattering of SW radiation from diatomic, triatomic, and symmetric-and asymmetric-top polyatomic molecules are outlined.     

X-ray structure analysis of the polycrystalline complex of copper (II) chloride with 1,5-dimethyltetrazole. Application of synchrotron radiation and laboratory diffraction data

The structure of the complex of copper (II) chloride CuCl₂ L, where L is 1,5-dimethyltetrazole, was refined with the Rietveld method using three sets of powder diffraction data obtained at laboratory diffractometers and with synchrotron radiation. The comparative analysis of the results of the structure refinement was performed; this analysis showed that the application of the laboratory data for the wavelength of X-rays λ = 1.7902 Å (CoKα radiation) provides the structural characteristics of the complex comparable in accuracy with those obtained using the synchrotron radiation for the wavelength λ = 1.5443 Å.     

X-ray spectroscopy of multiply-charged ions from laser plasmas

Original results are reported on the observation and identification of spectra of multiply-charged ions in the range of λ ≈ 1.5–15 Å, which corresponds to transitions with a range of principal quantum number n. The main part of the review consists of tables with about a thousand spectral lines, which have been mainly observed in laser-plasma radiation, as well as in the solar corona and other laboratory sources at an electron temperature T_e≈10⁷°K. The accuracy for the wavelengths (Δλ) is the following: Δλ is equal to ≈ 0.0005 Å for λ ≈ 2.5 Å and it is equal to ≈ 0.003 Å for λ ≈ 15 Å. The spectral lines are considered for the following transitions: 1-n type for [H]-like ions (Z = 11–16)and [He]-like ions (Z = 11–26); 2-n type for [Li]-like ions (Z = 19–26), [Be]-like ions (Z = 22–34) and [Ne]-like ions (Z = 26–42); 3-n type [Co]- and [Ni]-like ions (Z = 73). The line-list contains about four hundred wavelengths for multiply-charged iron L-ions (Fe(XVII)-Fe(XXIV)) and is presented with identification of some of the transitions. The wavelengths and intensities of satellites of the [H]-like ions and [He]-like ions, which are caused by transitions from the doubly-excited autoionization states 2l2l′ and 1s2l2L′ of [He]-like ions (Z = 11–16) and [Li]-like ions (Z = 11–26), respectively, are also considered.     

Observations of four-wave mixing processes in barium vapour

Emission at fifty discrete wavelengths is observed when Ba I is excited by two laser beams, a dye laser tuned to the λ 7911 Å intercombination line, 6s²¹S₀-6s6p ³P₁ and a ruby laser. The wavelengths range from 2312 Å to 8027 Å. Most of the emission lines can be attributed to four-wave mixing processes in barium.     

Efficient discharge pumping XeCl laser

Pulsed oscillation from XeCl at λ = 3080 Å has been obtained by exciting a mixture of He:Xe:BCl₃ at pressures of 1 to 7 atm with a transverse discharge. The laser efficiency relative to the discharge absorbed energy exceeds 1%. The role of dissociation recombination in the processes of excitation of XeCl¹ is discussed.     

15N Isotopic Effects on the Raman Spectra of Tribromoacetamide

Abstract

¹⁵N-Tribromoacetamide has been synthesized with an isotopic content of 99, 4%, its Raman spectra have been recorded in the range 4.000–50 cm^?1. The isotopic shifts arising from ¹⁵N have been determined and interpreted. We have assigned the vibrational spectra of Br₃CCONH₂ and some overtones, combinations and difference bands. The molecular structure of tribromoacetamide has been studied employing the Ab Initio teoretical calculations and the Teller - Redlich isotopic product rule has been applied by assuming these geometrical parameters:

rCN = 1.4623 Å, rCC = 1.6014 Å, rBrC = 1.9468 Å, rCO = 1.2144 Å, rNH = 1.0292 Å, C-C-Br = 108.83320, C-C-0:118.2440, C-C-N:120.4137, C-N-H:110.45930     

On the n = 1 exciton line of the green series in Cu2O

The weak isotropic line λ = 5830 Å observed on the wing of the yellow 2p-exciton line in Cu₂O is usually ascribed to the 1s(Γ⁺₄)-exciton of the green series. It is shown that if this is correct, then the stronger anisotropic line associated with the 1s(Γ⁺₅)-exciton of the green series should be nearly observed.     

Laser induced line narrowing in three-level systems: Application to the determination of the wavenumber of the 3s2-2p4 neon line (λ = 6328 Å)

The Doppler-free absorption line narrowing technique (A.L.N.) is applied to the ²⁰Ne (3s₂-2p₄-1s₅) three-level system, using a ¹²⁷I₂ stabilized He-Ne laser (λ = 6328 Å) and a tunable single-frequency cw dye laser (λ = 5945 Å). The relative frequency positions of the ²⁰Ne 3s₂-2p₄ line and of some iodine hyperfine components are measured with an uncertainty of 1 MHz. The wavenumber of the ²⁰Ne line at low pressure (0.2 Torr) is deduced from these measurements and is found to be σ(²⁰Ne, 3s₂-2p₄) = 1579800.060 ± 0.005 m^-1. With regard to the previous results, the accuracy is increased by two orders of magnitude.     

Stark broadening of some C(I) and N(I) vacuum ultraviolet lines

Stark widths of 11 C(I) lines and 3 N(I) multiplets were measured in the wavelength range 1310 Å ⩽ λ ⩽ 2583 Å. Gas mixtures (Ar+CO₂, Ar+N₂ and Ar+CO₂+N₂) were used for production of plasmas in a wall-stabilized arc under atmospheric pressure. Results were provided by five experiments (T varies from 13,370 to 13,950 K and N_e from 1.13 x 10¹⁷ cm^-3 to 1.35 x 10¹⁷ cm^-3. Stark shifts were measured for 2 C(I) lines and the ion-broadening parameter A was evaluated for 7 C(I) lines using different methods. The Stark widths and shifts are generally in reasonable agreement with other experimental or theoretical values, while the estimated A values are much higher than those predicted by Griem's theory.     

Search for macroscopic CP violating forces using a neutron EDM spectrometer

The search for CP violating forces between nucleons in the so-called axion window of force ranges λ between 2 × 10^?5 m and 0.02 m is interesting because only little experimental information is available there. Axionlike particles would induce a pseudo-magnetic field for neutrons close to bulk matter. A laboratory search investigates neutron spin precession close to a heavy mirror using ultracold neutrons in a magnetic resonance spectrometer. From the absence of a shift of the magnetic resonance we established new constraints on the coupling strength of axion-like particles in terms of the product g _s g _p of scalar and pseudo-scalar dimensionless constants, as a function of the force range λ, g _s g _p λ² ≤ 2 × 10^?21 [cm²] (C.L.95%) for 10^?4 cm < λ < 1 cm. For 0.1 cm < λ < 1 cm previous limits are improved by 4 to 5 orders of magnitude.