Mössbauer study of the quasi-binary sections FeSn2-FeSb2 and FeSn2-FeTe2 of the corresponding ternary systems Fe-Sn-Sb and Fe-Sn-Te

⁵⁷Fe and¹¹⁹Sn Mössbauer and X-ray diffraction studies have been performed at room temperature to establish the presence of various intermediate phases in the quasibinary sections FeSn₂-FeSb₂ and FeSn₂-FeTe₂ {i.e. Fe (Sn_1–xSb_x)₂ and Fe (Sn_1–xTe_x)₂ for 0x1·0 of the respective ternary systems Fe-Sn-Sb and Fe-Sn-Te at 500°C. Using significantly different Mössbauer hyperfine parameters and the X-ray powder diffraction patterns for each existing stable phase, solid solubility limits and presence of single and multiphase regions have been estimated and are reported.     

Status and Plan of the HL-2A Project

HL-2A is a new divertor tokamak under construction at Southwestern Institute of Physics (SWIP), Chengdu, China, based on the experience from HL-1 and HL-1M. HL is the short term of a Chinese word that means “ Toroidal Current Device“ . The main objectives of HL-2A are to produce more adaptable divertor configurations to study energy exhaust and impurity control(the first divertor tokamak plasma in China), and to study enhanced plasma confinement by profile control and moderate plasma shaping.     

Update of g-2 of the muon and Δα

We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions （5） 2 to the running of the QED coupling, Δαbad^5）（MZ^2）. Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV.     

Fundamental and combination bands of CO2–C2H2 and CO2–C2D2 in the mid-infrared region

Spectra of the weakly bound CO₂–C₂H₂ and CO₂–C₂D₂ complexes are observed in the regions of CO₂ ν₃ (≈ 2349 cm^?1) and C₂D₂ ν₃ (≈ 2440 cm^?1) fundamental vibrations, using an infrared optical parametric oscillator to probe a pulsed supersonic slit-jet expansion. Five bands are measured and analysed: the fundamental asymmetric stretch of the C₂D₂ component, two combination bands involving the out-of-plane torsional vibrations (C₂D₂ ν₃ + torsion and CO₂ ν₃ + torsion) for CO₂–C₂D₂, and two combination bands involving an intermolecular in-plane bending vibration for CO₂–C₂H₂ and CO₂–C₂D₂. The resulting intermolecular frequencies are 61.408(1), 54.5(5), 39.9(5), and 39.961(1) cm^?1 for CO₂–C₂H₂ and CO₂–C₂D₂ in-plane vibrations, and CO₂–C₂D₂ out-of-plane torsional vibrations in CO₂ and C₂D₂ regions, respectively. This is the first experimental determination of these intermolecular vibrational frequencies.     

Phase Transition in Ag2S and the Relative Position of Atomic Planes of the α-Ag2S and β-Ag2S Phases

JETP Letters - The relative position of atomic planes of low-temperature monoclinic acanthite α-Ag2S and high-temperature bcc argentite β-Ag2S has been determined from X-ray and electron...     

Influence of the reagent vibration on the stereo-dynamics of the reactions D^- ＋ H2 and H^- ＋ D2

Employing the quasi-classical trajectory method and the potential energy surface of Panda and Sathyamurhy [Panda A N and Sathyamurthy N 2004 J.Chem.Phys.121 9343],the effect of the reagent vibration on vector correlation of the ion-molecule reactions D～-+H₂ and H～-+D₂ is studied at a collision energy of 35.7 kcal/mol.Four generalized polarization-dependent differential cross sections （2π/σ）（dσ 00 /dωt）,（2π/σ）（dσ 20 /dωt）,（2π/σ）（dσ 22+ /dωt）,and （2π/σ）（dσ 21 /dωt） are presented in the centre-of-mass reference frame,separately.At the same time,the effects on the product angular distributions P （θr）,P （φr） and P （θr,φr） of the title reactions are also analysed.The calculated results show that the scattering tendencies of the product HD,the alignment and the orientation of j sensitively depend on reagent molecule vibration.     

Structure and stability of various states of the EuC and EuC2 molecules

B3LYP level density functional theory （DFT） and multiconfiguration self-consistent-field （MCSCF） level ab initio method calculations have been performed on the basis of relativistic effective core potentials to investigate the nature of EuC and EuC2 molecules. The computed results indicate that the ground states of EuC and EuC2 are ^12∑^＋ and SA2, respectively. Dissociation potential energy curves of the low-lying electronic states of EuC have been calculated using the MCSCF method, and the same level calculation on EuC2 indicates that the dissociation energy of EuC2 of ground state compares well with the available experimental data. The bond characteristic is also discussed using Mulliken populations.     

Elasticity of the B2 phase and the effect of the B1–B2 phase transition on the elasticity of MgO

A study of the high-pressure anisotropy of MgO was conducted using first-principles calculations based on density functional theory within the generalized gradient approximations. The pressure dependence of the elastic stiffness coefficients and the anisotropy parameters, in both B1 and B2 phases, shows that for high-hydrostatic compression the easiest deformation is the shear along (100) plane and the the material's response to deformation and to shearing strains is quite the same. According to the calculations of the velocities of propagation of elastic waves, we deduced that MgO develop an elastic anisotropy, especially, in the B1 phase. We present the B2 phase elastic properties which are not already studied under high pressure.     

Carbon-13 Assignments and Revision of the Stereostructures of the Cadinanes 2-Hydroxy-8α-angeloyloxycalamenene and 2-Hydroxy-8α-hydroxycalamenene

The two known cadinanes 2-hydroxy-8α-hydroxycalamenene and 2-hydroxy-8α-angeloyloxycalamenene were isolated from a Louisiana population of Heterotheca subaxillaris.

Their ¹³C NMR spectra were fully assigned by the application of HETCOR, COLOC, COSY, NOESY and DEPT experiments. It was shown on the basis of NOESY experiments that both cadinanes require revision at the stereogenic centre C-7.     

Development and Application of the 2D Relativistic Fokker-Planck Package

The Fokker Planck package which without the relativity effect has been developed in 2002. The package with relativity effect, which induced from Italy, is now developed. It conrains relativity effect, and is bounce averaged. It can deal with such as the trapping effect, wave heating, neutral beam injecting, and particle losses. It is very useful for our HL-2A experimental results analysis.     

Update of g-2 of the muon and △α

We update our Standard Model predictions for g-2 of the muon and for the hadronic contributions to the running of the QED coupling,αh(5a)d(MZ2).Particular emphasis is put on recent changes in the hadronic contributions from new data in the 2π channel and from the energy region just below 2 GeV.     

The nuclear deformation versus the spin-flip like excitations and the suppression of the 2νββ decay amplitude

The suppression mechanism of the Gamow-Teller double beta decay amplitude M_GT is studied using a many body Hamiltonian which describes a composite system of protons and neutrons moving in a projected spherical single particle basis. Alike nucleons interact through pairing while protons and neutrons by a separable dipole-dipole force both in the particle-hole (ph) and particle-particle (pp) channels. The spin-flip and non-spin-flip components of the QRPA phonons have a differents contribution to the M_GT values. The relative magnitudes and phases depend both on the strength of the particle-particle interaction (g_pp) and on the nuclear deformation. The deformation yields a fragmentation of the M_GT value on one hand and washes out the separation of states of pure spin-flip and non-spin-flip structures. Due to this effect M_GT has only one fragmented resonance structure in the low part of the spectrum.     

Optical properties of glasses activated by the compounds CuInSe2 and CuInTe2 and by the solid solutions CuInSe2x Te(1−x)

The spectral properties of amorphous media synthesized on the basis of glasses of the system SiO₂-CaO-R₂O (R=Na, K, Li), the ternary compounds CuInSe₂, and CuInTe₂, and solid solutions based on them have been investigated. It is shown that the absorption limit of the media investigated lies within 1.4–1.6 μm. It is noted that the three alkali ions constituting the system exert a favorable influence on the state and optical properties of the amorphous media activated with the compound CuInTe₂ and with the solid solutions CuInSe_2xTe_(1−x), where x≤0.5. The influence of the concentration of the solid solution CuInSeTe (x=0.5) on the optical properties of the amorphous media is investigated. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 132–134, January–February, 2000.     

Accurate potential energy function and spectroscopic study of the X^2∑＋, A^2П and B^2∑＋ states of the CP radical

This paper calculates the equilibrium internuclear separations, the harmonic frequencies and the potential energy curves of the X^2∑＋, A^2П and B^2∑＋ states of the CP radical by the highly accurate valence internally contracted multireference configuration interaction method with correlation-consistent basis sets （aug-cc-pV6Z for C atom and aug-cc-pVQZ for P atom）. The potential energy curves are all fitted with the analytic potential energy function by the least-square fitting. Employing the analytic potential energy function, we determine the spectroscopic constants （Be, αe and ωeχe） of these states. For the X2∑＋ state, the obtained values of De, Be, αe, ωeχe, Re and ωe are 5.4831 eV, 0.792119 cm-1, 0.005521 cm-1, 6.89653 cm-1, 0.15683 nm, 12535.11 cm-1, respectively. For the A2H state, the present values of De, Be,αe, ωeχe, Re and We are 4.586 eV, 0.703333 cm-1, 0.005458 cm-1, 6.03398 cm-1, 0.16613 nm, 1057.89 cm-1, respectively. For the B2E＋ state, the present values of De, Be, αe, ωeχe, Re and We are 3.506 eV, 0.677561 cm-1, 0.00603298 cm-1, 5.68809 cm-1, 0.1696 nm, 822.554 cm-1, respectively. For these states, the vibrational states with the rotational quantum number J equals zero （J = 0） are studied by solving the radial nuclear Schr6dinger equation using the Numerov method. For each vibrational state, the vibrational level, the classical turning points, the rotational inertial and the centrifugal distortion constants are calculated. Comparison is made with recent theoretical and experimental results.     

High resolution infrared study of the 2ν9 and ν4 bands of 10BF2OH and 11BF2OH: evidence of large amplitude effects for the OH-torsion and OH-bending modes in the 92 and 41 excited states

High resolution (2–3?×?10^?3?cm^?1) Fourier transform infrared spectra of gas phase ¹⁰B and ¹¹B enriched and natural samples of BF₂OH (difluoroboric acid) were recorded at Wuppertal and Richland. Starting from the results of previous studies, it was possible to perform the first rovibrational analysis of the 2ν₉ (first overtone of ν₉, the OH torsion) and ν₄ (BOH bending) bands located at about 1043.9 and 961.7?cm^?1 and 1042.9 and 961.5?cm^?1 for the ¹⁰BF₂OH and ¹¹BF₂OH isotopic species, respectively. Numerous ‘classical’ perturbations were observed in the analysis of the 2ν₉ and ν₄ bands. The energy levels of the 9² bright state are indeed involved in a B-type Coriolis resonance with those of the 6¹9¹ dark state. The 4¹ levels are perturbed by a B-type Coriolis resonance and by an anharmonic resonance with the levels of the 7¹9¹ and the 6¹7¹ dark states, respectively. In addition large amplitude effects were observed for the 2ν₉ and also, more surprisingly, the ν₄ bands. This results in splittings of the energy levels of about 0.005 and 0.0035?cm^?1 for the 9² and 4¹ states, respectively, which are easily observable in the P and R branches for both bands. The theoretical model used to reproduce the experimental levels accounts for the classical vibration–rotation resonances. Also the large amplitude torsional (or bending) effects are accounted for within the frame of the IAM (Internal Axis Method)-like approach. The Coriolis resonances between the two torsional (or bending) substates are taken into account by {J_x,?J_z} non orthorhombic terms in the v-diagonal blocks. This means that the z-quantification axis deviates from the a inertial axis by an axis switching effect of ～35° for the {9²,?6¹9¹} system and of ～16.6° for the {4¹,?7¹9¹,?6¹7¹} system of interacting vibrational states. The calculation of the relative line intensities for the 2ν₉ and ν₄ bands accounts for these axis switching effects as well as for the intensity alternation which is due to the nuclear spin statistical weights since the OH large amplitude torsion and/or bending motion results indeed in an exchange of the two fluorine nuclei.     

Accurate potential energy function and spectroscopic study of the X~2Σ~+,A~2Ⅱ and B~2Σ~+ states of the CP radical

This paper calculates the equilibrium internuclear separations,the harmonic frequencies and the potential energy curves of the X 2 Σ +,A 2Ⅱ and B 2 Σ + states of the CP radical by the highly accurate valence internally contracted multireference configuration interaction method with correlation-consistent basis sets(aug-cc-pV6Z for C atom and aug-cc-pVQZ for P atom).The potential energy curves are all fitted with the analytic potential energy function by the least-square fitting.Employing the analytic potential energy function,we determine the spectroscopic constants(B e,α e and ω e χ e) of these states.For the X 2 Σ + state,the obtained values of D e,B e,α e,ω e χ e,R e and ω e are 5.4831 eV,0.792119 cm 1,0.005521 cm 1,6.89653 cm 1,0.15683 nm,12535.11 cm 1,respectively.For the A 2Ⅱ state,the present values of D e,B e,α e,ω e χ e,R e and ω e are 4.586 eV,0.703333 cm 1,0.005458 cm 1,6.03398 cm 1,0.16613 nm,1057.89 cm 1,respectively.For the B 2 Σ + state,the present values of D e,B e,α e,ω e χ e,R e and ω e are 3.506 eV,0.677561 cm 1,0.00603298 cm 1,5.68809 cm 1,0.1696 nm,822.554 cm 1,respectively.For these states,the vibrational states with the rotational quantum number J equals zero(J = 0) are studied by solving the radial nuclear Schro¨dinger equation using the Numerov method.For each vibrational state,the vibrational level,the classical turning points,the rotational inertial and the centrifugal distortion constants are calculated.Comparison is made with recent theoretical and experimental results.     

B 2Σ u + excited states of the N + 2 ion and the electron temperature in the discharge afterglow of an Ar-N2 mixture

The electron energy distribution function in the afterglow of a low-pressure discharge in an Ar-N₂ mixture was experimentally found. The values of electron temperature were determined. At the initial stage of plasma decay, the electron temperature was shown to be close to the nitrogen vibrational temperature. A study was made of the afterglow observed in the bands of the first negative system of N ₊ ² , and it is shown that this afterglow may be attributed to collisions of argon ions with nitrogen molecules found on higher vibrational levels.     

What controls the phase diagram and superconductivity in Ru-substituted BaFe2As2?

We use high resolution angle-resolved photoemission to study the electronic structure of the iron based high-temperature superconductors Ba(Fe(1-x)Ru(x))(2)As(2) as a function of Ru concentration. We find that substitution of Ru for Fe is isoelectronic, i.e., it does not change the value of the chemical potential. More interestingly, there are no measured, significant changes in the shape of the Fermi surface or in the Fermi velocity over a wide range of substitution levels (0相似文献   

Analysis of the High-Resolution Infrared Spectrum of the PHD2 Molecule: ν1 and 2ν1 Bands

The results of investigation into the infrared spectra of the PHD₂ molecule including the ₁ fundamental band centered at 2324.005 cm^–1 (with a resolution of 4.2·10^–3 cm^–1) and the first 2₁ valence overtone centered at 4563.634 cm^–1 (with a resolution of 8.8·10^–3 cm^–1) are given in the present paper. Based on an analysis of the results obtained, 1340 and 1020 lines are referred to the ₁ and 2₁ bands, respectively. This data are used to calculate 316 and 248 vibrational-rotational energies of the (100000) and (200000) excited vibrational states, respectively. Since both bands can be considered as isolated, we take advantage of the Watson Hamiltonian (the reduction A in the I ^r representation) to describe their rotational structure. The calculated spectroscopic parameters of the examined states of the PHD₂ molecule correlate well with each other and with the corresponding parameters of the ground vibrational state.