Theoretical prediction of A(3)0+ <-- X(1)0+ and B(3)1 <-- X(1)0+ spectra of the Zn-rare gas van der Waal's molecules.

Excitation spectra arising from A(3)0+ <-- X(1)0+ and B(3)1 <-- X(1)0+ electronic transitions in the Zn-rare gas (RG) van der Waal's molecules are calculated using the newly obtained ab initio potential curves for these species. The radial Schr?dinger equation for nuclear motion was solved numerically with the calculated potentials to evaluate the corresponding vibrational levels and radial wavefunctions for the ground X(1)0+ and excited A(3)0+ and B(3)1 states of the Zn-RG complexes. The wavefunctions have been subsequently used in the calculation of the appropriate Franck-Condon factors to yield information on relative intensities of the vibrational bands produced by A(3)0+ <-- X(1)0+ and B(3)1 <-- X(1)0+ transitions.     

The diffusion-limited reaction A + A →0 in the steady state: influence of correlations in the source

We study theoretically the kinetics of the diffusion-limited reaction + →0 in the steady state. We consider the effect of an external source which adds correlated pairs of particles. We show that in dimensions below 2 and in the low-density limit spatial self-organization of reactants occurs and is controlled by the correlation in the source term. At higher densities there is a crossover to a regime similar to the random landing case, exhibiting a non-classical order of reaction.     

The polarization dependent differential cross sections of the reactions:H+LiH~+(v=0,j=0)→H_2+Li~+ and H~++ LiH(v=0,j=0)→H_2~++Li

<正>Quasi-classical trajectory(QCT) calculations have been carried out to study the generalized polarization dependent differentialcross sections(PDDCSs) for the reactions H + LiH~+(v = 0,j = 0)→H_2 + Li~+ and H~+ + LiH(v = 0,j = 0)→H_2~+ + Li occurring onthe two lowest-lying electronic states of the LiH_2~+ system,using the ab initio potential energy surfaces(PESs) of Martinazzo et al.[3].Four PDDCSs,i.e.,(2π/σ)(dσ_(00)/dω_t),(2π/σ)(dσ_(20)/dω_t),(2π/σ)(dσ_(22+)/dω_t),(2π/σ)(dσ_(21-)/dω_t) have been discussed in detail.     

A unified theory of spin 0 nuclear interactions

A Gauge Theory that contains the pion triplet as strong force quanta, a quantum theory of gravity and unifies the strong (nuclear) and gravitational interactions is proposed under a relaxation of the requirement of covariance for Lorentz boost transformations. A modified form of local gauge invariance in which the nucleon field phase is allowed to vary with each time point but not each space point leads to the introduction of a new compensatory field. The quanta of this field are massless spin 0 particles that propagate at the speed of light. They are interpreted as gravitons which mediate the Newtonian gravitational force. It is suggested that the universality of the interaction is linked with the conservation of mass. The associated equation of motion yields Newton's Inverse Square Law for the static case and, because of retardation of potentials, gives rise to a precession of planetary orbits. A qualitative indication of the energy loss observed in the binary pulsar PSR1913+16 within the Newtonian framework is also given. A modification of the Yang–Mills invariance is applied to nucleons. It requires the strong interaction between nucleons to be invariant under independent rotations of the isotopic spin at each time point but not each space point. This results in the introduction of a triplet of compensating fields having massless spin 0 quanta that are interpreted as massless pions. An SU(2)×U(1) theory combining isotopic spin and hypermass symmetries is then developed. Spontaneous Symmetry Breaking yields three massive particles (along with a Higgs particle) and one massless particle. The three massive particles have mass, spin and charge that identify them as pions, while the single massless spin 0 particle, which couples to the nucleons with a strength proportional to mass, is interpreted as the spin 0 graviton. The model provides a resolution of one of the outstanding puzzles of theoretical physics: why gravity is so much weaker than the other forces of nature.     

Intermodulated fluorescence spectroscopy of caf AΠ-XΠ

The A ²Π-X²∑⁺ 0-0 transition of CaF has been examined by the technique of intermodulated fluorescence spectroscopy (“Lamb dip”). The hyperfine structure due to ¹⁹F and the spin-rotation fine structure of the X ²∑⁺ state was determined. Parameter values of b = 104.0 (9) MHz, c = 58(6) MHz and γ = 38.6(2) MHz were found for v = 0 of X²∑⁺     

Yb<Superscript>3+</Superscript> doped dyphillosilicates prepared by thermally induced phase transformation of zeolites

Yb³⁺-doped Ba and Sr diphyllosilicates (hexacelsians) have been synthesized using the Na form of LTA zeolite by ion-exchange procedure and thermal treatment. The crystal structures of both doped samples are refined and described in this article. The results of Rietveld refinements clearly indicate that Yb³⁺ ions are incorporated into the hexacelsians structure. AFM photomicrographs show round-shaped particles with the size of few microns. The magnetization measurements were done within the 2–300 K temperature range, revealing an enhancement of magnetization with temperature that is not in accordance with simple paramagnetic behavior. The text was submitted by the authors in English.     

On the dynamics of the H+ +D2(v=0,j=0)-->HD+D + reaction: a comparison between theory and experiment

The H+ +D2(v=0,j=0)-->HD+D + reaction has been theoretically investigated by means of a time independent exact quantum mechanical approach, a quantum wave packet calculation within an adiabatic centrifugal sudden approximation, a statistical quantum model, and a quasiclassical trajectory calculation. Besides reaction probabilities as a function of collision energy at different values of the total angular momentum, J, special emphasis has been made at two specific collision energies, 0.1 and 0.524 eV. The occurrence of distinctive dynamical behavior at these two energies is analyzed in some detail. An extensive comparison with previous experimental measurements on the Rydberg H atom with D2 molecules has been carried out at the higher collision energy. In particular, the present theoretical results have been employed to perform simulations of the experimental kinetic energy spectra.     

钙钛矿结构荧光材料MZrO3:Eu3+,A (M=Ca2+, Ba2+; A=Li+, Na+, K+)的制备及其发光性质

Calcium and barium zirconate powders based upon CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) were prepared by combustion synthesis method and heating to ~1000℃ to improve crystallinity.The structure and morphology of materials were examined by X-ray diffraction (XRD) and scanningelectron microscopy (SEM). XRD results showed that CaZrO₃:Eu³⁺,A and BaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) perovskites possessed orthorhombic and cubic structures, respectively. The morphologies of all powderswere very similar consisting of small, coagulated, cubical particles with narrow size distributions andsmooth and regular surfaces. The characteristic luminescences of Eu³⁺ ions in CaZrO₃:Eu³⁺,A (A=Li⁺, Na⁺, K⁺) lattices were present with strong emissions at 614 and 625 nm for ⁵D₀→⁷F₂ transitions with other weakeremissions observed at 575, 592, 655, and 701 nm corresponding to ⁵D₀→⁷F_n transitions (where n=0, 1, 3, 4 respectively). In BaZrO₃:Eu³⁺ both the ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ transitions at 595 and 613 nm were strong.Photoluminescence intensities of CaZrO₃:Eu³⁺ samples were higher than those of BaZrO₃:Eu³⁺ lattices. Thisremarkable increase of photoluminescence intensity (corresponding to ⁵D₀→⁷F_n transitions) was observedin CaZrO₃:Eu³⁺ and BaZrO₃:Eu³⁺ if co-doped with Li⁺ ions. An additional broad band composed of manypeaks between 440 to 575 nm was observed in BaZrO₃:Eu³⁺,,A samples. The intensity of this band wasgreatest in Li⁺ co-doped samples and lowest for K⁺ doped samples.     

A time-dependent wave packet quantum scattering study of the reaction HD+ (v = 0 - 3;j0 = 1) + He --> HeH+(HeD+) + D(H)

Time-dependent wave packet quantum scattering (TWQS) calculations are presented for HD(+) (v = 0 - 3;j(0)=1) + He collisions in the center-of-mass collision energy (E(T)) range of 0.0-2.0 eV. The present TWQS approach accounts for Coriolis coupling and uses the ab initio potential energy surface of Palmieri et al. [Mol. Phys. 98, 1839 (2000)]. For a fixed total angular momentum J, the energy dependence of reaction probabilities exhibits quantum resonance structure. The resonances are more pronounced for low J values and for the HeH(+) + D channel than for the HeD(+) + H channel and are particularly prominent near threshold. The quantum effects are no longer discernable in the integral cross sections, which compare closely to quasiclassical trajectory calculations conducted on the same potential energy surface. The integral cross sections also compare well to recent state-selected experimental values over the same reactant and translational energy range. Classical impulsive dynamics and steric arguments can account for the significant isotope effect in favor of the deuteron transfer channel observed for HD(+)(v<3) and low translational energies. At higher reactant energies, angular momentum constraints favor the proton-transfer channel, and isotopic differences in the integral cross sections are no longer significant. The integral cross sections as well as the J dependence of partial cross sections exhibit a significant alignment effect in favor of collisions with the HD(+) rotational angular momentum vector perpendicular to the Jacobi R coordinate. This effect is most pronounced for the proton-transfer channel at low vibrational and translational energies.     

The effect of the initial reactant molar ratio and doping with Fe<Superscript>3+</Superscript> on the formation of calcium bilirubinate in water-oil microemulsions

A series of calcium bilirubinate nanoparticles were synthesized in microemulsions consisting of polyoxyethylene octylphenol ether (Triton X-100), n-hexyl alcohol (n-C₆H₁₃OH), cyclohexane (c-C₆H₁₂), and an aqueous solution. The particles were characterized by Fourier transform infrared (FT-IR) spectra, powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES), transmission electron microscopy (TEM), and zeta potential measurements. The results showed that the initial CaCl₂/Na₂BR molar ratio and the molar ratio of water to surfactant (ω₀) influenced the morphology and microstructure of calcium bilirubinate nanoparticles and the sites of Ca²⁺ coordination to BR²⁻. The composition of synthesized calcium bilirubinate was nonstoichiometric. The stability of calcium bilirubinate nanoparticles dispersed in water changes as the Ca²⁺/BR²⁻ molar ratio and solution pH varied. Dopant Fe²⁺ ions played a certain role in the simulated mineralization of calcium bilirubinate. A possible mechanism of calcium bilirubinate formation in inverse microemulsions is discussed. The text was submitted by the authors in English.     

The A Πu-X Πg emission spectrum of I2

The A ²Π_u-X ²Π_g electronic emission spectrum of I₂⁺ has been recorded at a low rotational temperature in a crossed molecular beam/electron beam apparatus. Six vibrational sequences with five or more members have been assigned to progressions in ν′, giving ω′_e = 122±8 cm⁻¹, but a full vibrational analysis has not been possible. It is not known whether this is due to the relatively poor resolution (≈5 cm⁻¹) at which the spectrum has been recorded or because the A ²Π_u state is perturbed in one or both spin-orbit components. Existing data on the A state of I₂⁺ are reviewed.     

Time dependent quantum dynamics study of the Ne + H2+(v=0-4)-->NeH+ + H proton transfer reaction

The Ne + H2+-->NeH+ + H proton transfer reaction was studied using the time dependent real wave packet quantum dynamics method at the helicity decoupling level, considering the H2+ molecular ion in the (v=0-4, j=0) vibrorotational states and a wide collision energy interval. The calculated reaction probabilities and reaction cross sections were in a rather good agreement with reanalyzed previous exact quantum dynamics results, where a much smaller collision energy interval was considered. Also, a quite good agreement with experimental data was found. These results suggested the adequacy of the approach used here to describe this and related systems.     

H+O2(n0, j0)→HO+O及C+H2(n0, j0)→CH+H体系选态反应截面的过渡态理论计算

本文用微正则过渡态理论计算了H+O_2(n_0,j_0)→HO+O和C+H_2(n_0, j_0)→CH+H在ab initio势能面上的选态反应截面σ_(n_0,j_0); E.分析了势能面性质对反应截面的影响。计算结果表明, 在指定反应物分子的振动态n_0、转动态j_0时, 两个反应体系的反应截面随相对平动能的增加先是增加后是减小(j_0=1, n_0=0除外); 在给定相对平动能和反应物分子的转动态j_0时, 随反应物分子的振动量子数n_0的增加, 两个体系的选态反应截面均有较显著的增加, 在指定相对平动能和反应物分子的振动态n_0时, H+O_2体系的选态反应截面随j_0的变化较为复杂, 而C+H_2体系则比较简单(j_0=1除外)。对于H+O_2反应体系, 本文得到的反应截面与实验结果及准经典轨迹理论的计算结果符合得很好。     

VLE of CO2 + glycerol + (ethanol or 1-propanol or 1-butanol)

Vapour-liquid equilibrium of CO₂ + [0.00871 glycerol + 0.99129 (ethanol or 1-propanol or 1-butanol)] mixtures was measured at the temperatures of 313.15 K and 333.15 K, and close to the critical line, at pressures up to 12 MPa. On the liquid side, the bubble points measured for these ternary mixtures follow closely the behaviour of VLE reported by several authors for the corresponding binary mixtures without glycerol. On the vapour side, however, dew points for the ternary mixtures deviate significantly from VLE results for the binaries. A correlation of the results obtained for the CO₂ + glycerol + ethanol mixture with the Peng-Robinson equation of state, admitting quasi-binary behaviour, equally yields good agreement on the liquid side, and significant deviations on the vapour side.     

A comparison of attack angle dependence of exchange channel of reaction H + HS (v = 0, 1; j = 0) on 3A″ and 3A′ surfaces

In this theoretical work, we report quasiclassical dynamics predictions for the attack angle‐dependence exchange processes for the H + HS (v = 0, 1; j = 0) reaction by using the new triplet 3A″ and 3A′ potential energy surfaces, respectively. The calculated quasiclassical reaction probabilities of exchange reaction channel of reaction H(D)′ + H(D)S for J = 0, 10, 20, 30, 40 are in good agreement with quantum wave packet results over the collision energy range from 0.1 to 2.0 eV on 3A″ surfaces. The attack angle dependence reaction probability of the title reactions at J = 0 are calculated, respectively, on the two surfaces. The reaction probability was found to be strongly dependent on the attack angle. It may be ascribe to the significant difference of the effective potential barrier height in the two reactions. Besides, the reaction probabilities of exchange reaction channel of reaction H(D)′ + H(D)S for J = 0, 10, 20, 30, 40 are also predicted on 3A′ surfaces. © 2013 Wiley Periodicals, Inc.     

The composition, charge and architecture of hydronium ions as observed in the crystalline state

The structures of hydronium ions present in single crystals have, by and large, been thought as being relatively simple and characterized by the classical formulae H₃O⁺, , and . All of them are thought to be quasi-planar, acyclic entities of charge +1, exclusively. In this review, we show that such is not the case in view of the fact that there exist documented examples of cyclic hydronium ions, that their charge can be larger than +1 and that they exist in aggregates containing more than four oxygens. Moreover, it is documented that hydronium ions exist in the form of geometrical isomers or conformers. To cite this article: I. Bernal, C. R. Chimie 9 (2006).     

Anisotropic exchange interactions in hetero-one-dimensional Ln–M systems (Ln = Er,Yb; M = Cr,FeLS): Magnetometry and Dual Mode X-band Electron Paramagnetic Resonance spectroscopic studies

A recently introduced experimental and theoretical procedure is presented in order to calculate the magnitude and anisotropy of interaction between a lanthanide and a 3d-metal ion. The general formula of the hetero-one-dimensional molecular compounds is trans-[M(CN)₄(μ-CN)₂Ln(H₂O)₄(bpy)]_n·nH₂O · 1.5nbpy (M = Fe³⁺, Cr³⁺; Ln = Er³⁺, Yb³⁺), where bpy = 2,2′-bipyridine, abbreviated as [LnM] from now on. The main parts of this procedure are: (a) the evaluation of the effective g-parameters of the lanthanide ion with the help of EPR measurements; (b) the use of dual-mode EPR spectroscopy to define the anisotropic exchange interactions with the help of an anisotropic Hamiltonian model; (c) use of the same magnetic model to fit magnetization and susceptibility data in order to verify the EPR findings.     

Spin-forbidden c 3Sigma1+<--X 1Sigma+ band system of YF

Optical spectra of jet-cooled diatomic YF have been recorded using resonant two-photon ionization spectroscopy. A vibrational progression corresponding to the c 3Sigma1+<--X 1Sigma+ system has been identified. The vibrational frequency omegae' and anharmonicity omegae'xe' of the c 3Sigma+ state are 546.70 and 2.45 cm-1, respectively. The 0-0, 1-0, and 2-0 bands of the c 3Sigma1+<--X 1Sigma+ system were rotationally resolved and analyzed, allowing the v'=0, 1, and 2 levels of the c 3Sigma1+ substate to be characterized. From these studies, Be'=0.269 81(3) cm-1, alphae'=0.001 72(3) cm-1, and re'=1.9979(1) A were obtained (1sigma error limits). For these levels the spin-spin coupling constant lambdav is identical within experimental error, as lambda=-22.5 cm-1. The spin-forbidden c 3Sigma1+<--X 1Sigma+ transition is made allowed by spin-orbit interaction between the c 3Sigma1+ and the B 1Pi states. Excited state lifetimes of the c 3Sigma1+ and the B 1Pi states have been measured as 7.11(41) and 0.133(15) micros, respectively. A spin-orbit analysis shows that the c 3Sigma1+ state is contaminated with 2% B 1Pi character, which is approximately sufficient to explain the 7 micros lifetime of the c 3Sigma1+ state.     

Energy Transfer Between Eu3+ Ions and CdS Quantum Dots in Sol-Gel Derived CdS/SiO2 : Eu3+ Gel

We have investigated the energetic correlation between rare-earth ions and semiconductor nanocrystals, using europium ion (Eu³⁺) doped silica (SiO₂) gel with adsorbed cadmium sulfide (CdS) particles. Samples were prepared by a sol-gel technique, in which several methods for the precipitation of CdS colloids were attempted. The fluorescence intensities were compared for different gels, with and without CdS particles. The intrinsic emission lines due to ⁵D₀ ⁷F_J(J = 0–4) transitions of Eu³⁺ were observed, which were enhanced for 24 h-immersed gel (dried at 50°C). From the results on the decay dynamics of fluorescence, we proposed the model that surface-trapped electrons on CdS particles nonradiatively excited 4f electrons in Eu³⁺ ions due to an energy transfer process.     

Estimation of Critical Temperature of Thermal Explosion for Energetic Materials Based on Non-isothermal Kinetic Equation dα/dt =A_0 exp(bT)[1+(T–T_0 )b]f(α)

Critical temperature(T b ) of thermal explosion for energetic materials is estimated from Semenov’s thermal explosion theory and the non-isothermal kinetic equation dα/dt=A 0 exp(bT)[1+(T–T 0 )b]f(α) deduced via reasonable hypotheses, where T 0 is the initial point of the deviation from the baseline of DSC curve. The final formula is (T b –T e0 ){1+1/[1+( T b –T 00 )b]}=1. We can easily obtain the initial temperature(T 0i ) and onset temperature(T ei ) from the non-isothermal DSC curves, the values of T 00 and T e0 from the equation T 0i or ei =T 00 or e0 +α 1 β i +α 2 β i2 +…+α L–2 β iL –2 , i=1,2,…,L, the value of b from the equation: ln[β i /(T ei –T 0i )]=ln[A 0 /G(α)]+bT ei , so as to calculate the value of T b . The result obtained with this method coincides completely with the value of T b obtained by Hu-Yang-Liang-Wu method.