Quantum-mechanical calculation of the reactions D + FH(ν = 0, 1, 2) → DF(ν′) + H and H + FD(ν = 0, 1, 2, 3) → HF(ν′) + D on a realistic potential energy surface

Collinear (two-mathematical-dimensional (2MD)) coupled-channel quantum-mechanical calculations have been performed on the reactions D + FH(ν = 0, 1, 2) → DF(ν′) + H and H + FD(ν = 0, 1, 2, 3) → HF(ν′) + D on a potential energy surface with a 40 kcal/mole barrier to exchange. This barrier height is close to that predicted by ab initio calculations and suggested by experiments. The relative effectiveness of reagent vibrational and translational excitation to promote reaction is considered. A one-mathematical-dimensional (1MD) model for these reactions is constructed and is shown to work very well for the D + FH reaction at high temperatures, and less well for that reaction at lower temperatures as well as for the reverse H + FD reaction. Possible reasons for the breakdowns of this model are discussed.     

Capture and dissociation in the complex-forming CH(v = 0,1) + D2 → CHD + D, CD2 + H, CD + HD reactions and comparison with CH(v = 0,1) + H2

Rate coefficients for the CH(v = 0,1) + D(2) reaction have been determined for all possible channels (T: 200-1200 K), using the quasiclassical trajectory method and a suitable treatment of the zero point energy. Calculations have also been performed on the CH(v = 1) + H(2) reaction and the CH(v = 1) + D(2) → CH(v = 0) + D(2) process. Most of the results can be understood considering the key role played by the deep minimum of the potential energy surface (PES), the barrierless character of the PES, the energy of the reaction channels, and the kinematics. The good agreement found between theory and experiment for the rate coefficients of the capture process of CH(v = 0) + D(2), the total reactivity of CH(v = 1) + D(2), H(2), as well as the good agreement observed for the related CH(v = 0) + H(2) system (capture and abstraction), gives confidence on the theoretical rate coefficients obtained for the capture processes of CH(v = 1) + D(2), H(2), the individual reactive processes of CH(v = 1) + D(2), H(2), the abstraction and abstraction-exchange reactions for CH(v = 0) + D(2), and the inelastic process mentioned above, for which there are no experimental data available, and that can be useful in combustion chemistry and astrochemistry.     

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。     

H+O_2(n_0,j_0)→HO+O及C+H_2(n_0,j_0)→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。     

Valence of elements in HgBa_2Ca_(n-1)Cu_nO_(2n+2+δ)(n=1, 2, 3, 4)

HgBa2Can-1CunO2n+2+( (n=1, 2, 3, 4) 1 are tetragonal with space group space P4/mmm. For n=1,2,3, nearly single-phase crystals were obtained, while for n=4, the sample was primarily a mixture of the n=3 and 4 phases. These materials also possessed the highest Tc values yet observed for any superconductors. In this paper, the valences of elements in the title compounds were calculated from bond valence sum method 2. The calculated bond covalency, valences of elements were summarized in Table …     

Crystal Structure of (Hg, Ce, Cu)(Sr, Pr)2(Pr, Sr)Cu2O6+δ and (Hg, \square )(Sr, Pr)2(Pr, Sr)2Cu3O8+δ Phases

This paper reports on the refined compositions and crystal structures of two phases from the homologous series (Hg, M)(Sr, Pr)₂(Pr, Sr)_k-1Cu_kO_2k+2+ with k = 2 (Hg-1212) — (Hg_0.44(2)Ce _0.31 ⁴⁺ Cu_0.25)(Sr_0.90(3)Pr_0.10)₂(Pr_0.52(3)Sr_0.48)Cu_2.00O_7.00 (a = 3.8634(1), c = 12.2030(8) , space group P4/mmm) with k = 3 (Hg-1223) — (Hg_0.29(1) )(Sr_0.67(2)Pr_0.33)₂(Pr_0.61(2)Sr_0.39)₂Cu_3.00O_9.32(8) or (Hg_0.29(1) )(Sr_0.61(4)Pr_0.39)₂(Pr_0.51(4)Sr_0.49)₂Cu_3.00O_9.00 (with a fixed content of superstoichiometric oxygen O(4) in the phase) ( is a vacancy; a = 3.8294(9), b = 3.8567(6), c = 15.2763(44) , space group Pmmm). The implausibly high content of oxygen in the Hg-1223 phase (refinement I) is attributed either to O–O bond formation or to the possible presence of a minor amount of copper in a defect position of Hg; the inclusion of the latter in structure refinement leads to a better reproduction of the real structure but increases the R indices. The crystal-chemical analysis of the title phases and a comparison with the available data for analogous phases indicates that the composition of the crystallographic positions is related to structural features, in particular, to the coordinates of (Hg, M) and superstoichiometric oxygen, whose content depends on the degree of substitution of strontium ions by praseodymium ions. Reasons for the orthorhombic distortion of the Hg-1223 phase are discussed. The absence of superconductivity is explained by the nonoptimal formal charge (FC) of copper, which depends on the oxygen content in the phase.     

Liquid–liquid equilibrium data for binary alcohol + n-alkane (C10–C16) systems: methanol + decane,ethanol + tetradecane,and ethanol + hexadecane

Liquid–liquid equilibrium (LLE) data for three binary alcohol + n-alkane (C₁₀–C₁₆) systems—methanol + decane, ethanol + tetradecane, and ethanol + hexadecane—were measured using a laser scattering technique. The experimentally determined cloud points were satisfactorily correlated by three local composition models (NRTL, Tsuboka–Katayama’s modification of the Wilson equation, and the modified complete local composition model suggested by Nagata and Tamura). Prediction of vapor–liquid equilibria by means of these models with parameters obtained from the LLE data was also tested.     

Vapour–liquid equilibrium for the systems diethyl sulphide + 1-butene, +cis-2-butene, +2-methylpropane, +2-methylpropene, +n-butane, +trans-2-butene

Isothermal vapour–liquid equilibrium was measured for the systems of diethyl sulphide + 1-butene, +cis-2-butene, and +2-methylpropene at 312.6 K, diethyl sulphide + n-butane was measured at 317.6 K, diethyl sulphide + trans-2-butene at 317.5 K, and diethyl sulphide + 2-methylpropane at 308.0 K. The pressure–temperature–total composition data were converted into pressure–temperature–liquid–vapour composition data using the method of Barker. Error estimates are provided for each variable. The isothermal parameters for the Wilson, NRTL and UNIQUAC activity coefficient models were regressed. The measurements were compared with the predictions by COSMO segment activity coefficient (COSMO-SAC) and UNIFAC.     

H+HF(v,j)→H+HF(v′,j′)的传能动力学理论研究

本文运用非含时量子动力学方法研究了H+HF(v=1,j)→H+HF(v'=0,j')传能过程在295~500 K的振动弛豫速率常数.在此温度范围内,所有转动分辨的振动弛豫速率常数随着温度升高而单调递增,速率常数最大的末态转动量子数随着初态转动量子数的增加而增加.在室温下,振动态分辨的振动弛豫速率常数与实验值符合较好.同时,我们也计算了H+HF(v=1,j)→H+HF(v'=1,j')纯转动传能过程在500 K的速率常数,发现它们整体上比振动弛豫速率常数大了几个数量级,并且△j=-1的速率常数一般大于△j=-1的速率常数.     

Die Reaktion zwischen Thioglykols?ure (TGA) und Zn2+, Hg2+, Cd2+, Pb2+ und Ag+

Ohne Zusammenfassung     

铬-磷二元团簇(CrP+4, CrP+8)的量子化学研究

在相应的实验基础上，利用量子化学方法（DFT／B3LYP）对CrP4^ 和CrP8^ 的各种可能构型进行理论计算，预测了各团簇的稳定构型，所得结果能较好地说明有关团簇的光解实验结果。     

Accurate ab initio potential energy surface, thermochemistry, and dynamics of the Cl(2P, 2P(3/2) + CH4 → HCl + CH3 and H + CH3Cl reactions

We report a high-quality, ab initio, full-dimensional global potential energy surface (PES) for the Cl((2)P, (2)P(3/2)) + CH(4) reaction, which describes both the abstraction (HCl + CH(3)) and substitution (H + CH(3)Cl) channels. The analytical PES is a least-squares fit, using a basis of permutationally invariant polynomials, to roughly 16,000 ab initio energy points, obtained by an efficient composite method, including counterpoise and spin-orbit corrections for the entrance channel. This composite method is shown to provide accuracy almost equal to all-electron CCSD(T)/aug-cc-pCVQZ results, but at much lower computational cost. Details of the PES, as well as additional high-level benchmark characterization of structures and energetics are reported. The PES has classical barrier heights of 2650 and 15,060 cm(-1) (relative to Cl((2)P(3/2)) + CH(4)(eq)), respectively, for the abstraction and substitution reactions, in good agreement with the corresponding new computed benchmark values, 2670 and 14,720 cm(-1). The PES also accurately describes the potential wells in the entrance and exit channels for the abstraction reaction. Quasiclassical trajectory calculations using the PES show that (a) the inclusion of the spin-orbit corrections in the PES decreases the cross sections by a factor of 1.5-2.5 at low collision energies (E(coll)); (b) at E(coll) ≈ 13,000 cm(-1) the substitution channel opens and the H/HCl ratio increases rapidly with E(coll); (c) the maximum impact parameter (b(max)) for the abstraction reaction is ~6 bohr; whereas b(max) is only ~2 bohr for the substitution; (d) the HCl and CH(3) products are mainly in the vibrational ground state even at very high E(coll); and (e) the HCl rotational distributions are cold, in excellent agreement with experiment at E(coll) = 1280 cm(-1).     

M(bpy)2+3(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物Ｍ（ｂｐｙ）＾２＋３（Ｍ＝Ｆｅ,Ｒｕ,Ｏｓ）的量子化学密度泛函法研究的结果。Ｂ３ＬＹＰ／ＬａｎＬ２ＤＺ方法与基组的水平上进行计算,探讨Ｍ（ｂｐｙ）＾２＋３电子结构特征及相关性质,特别是中心原子对配合物的配位键长、光谱性质,电荷布局及化学稳定性等的影响规律,为该类配合物的合成,为分析光、电、催化作用机理提供理论参考。     

M(bpy)2+3(M=Fe,Ru,Os)电子结构与相关性质

报导了对配合物(M=Fe,Ru,Os)的量子化学密度泛函(DFT)法研究的结果.在B3LYP/LanL2DZ方法与基组的水平上进行计算,探讨的电子结构特征及相关性质,特别是中心原子对配合物的配位键长、光谱性质、电荷布居及化学稳定性等的影响规律,为该类配合物的合成,为分析光、电、催化作用机理提供理论参考.     

Phosphates M 0.5(1 + x) 2+ Cr x Ti2 − x (PO4)3: Synthesis, structure, and catalytic properties

Complex phosphates of titanium, chromium, and metals(2+) of the general formula M_{0.5(1 + x} )Cr _x Ti_{2 ? x} (PO₄)₃ (M = Mg, Ca, Mn, Ni, Sr, Ba, and Pb) were synthesized. Their phase formation was studied by means of X-ray powder diffraction, electron probe microanalysis, differential thermal analysis, and IR spectroscopy. Individual phases and solid solutions crystallizing in kosnarite and langbeinite structure types were identified; their crystallographic parameters were calculated. The catalytic properties of phosphates Ca_{0.5(1 + x} )Cr _x Ti_{2 ? x} (PO₄)₃ in methanol conversion were studied.     

Calculations of Chemical Reaction Dynamics for D+ H_2(j_i,ν_i=0)→DH(j_f, ν_f=0) + H

Thepastfewyearshavewitnessedanincreasinglevelofinterestinthestudyofchemicalreactiondyntalcsboththeoreticallyandexperimentallyt'J.EsPeciallythemolecularbeamexperimenthasrnaderemarkableprOgressandhasstimulatedtheoreticalstudies.Itis,h0wever,stillaverydiffcultproblemtocalculatereactioncrosssectionsandrateconstantsacctiratelyeveninthecaseofD+H2(j,,vi=O)-DH(jf,vf=O)+H,whichrepresentsthesdriplestbutmostfundamenta1reactionsystem.Someattemptshavebeenmadetompoutveryaccuratequantummechanica-lcalcula…     

State-selected ion-molecule reactions: H+2(ν) + He → HeH+ + H and He + H+ + H

Total cross sections for production of HeH⁺ and H⁺ in the reaction of state-selected H⁺₂ (v = 0 to 6) with He at 3.1 eV c.m. collision energy are measured by means of the threshold-photoelectron/photoion coincidence method, using pulsed synchrotron radiation. Both reaction cross sections are observed to rise with vibrational energy. The H⁺/HeH⁺ branching ratio, which is determined directly, remains approximately constant at about 0.3 for v ⩽ 3 and rises gradually for higher levels to reach the value 1.3 for v = 6. For v ⩽ 3 both reactions involve hard-type collisions and result in large-angle scattering. In contrast, at higher v levels, the HeH⁺ becomes essentially forward scattered with respect to the incident He direction, but with a velocity greater than that expected from the spectator stripping model. The H⁺ products are backward scattered with respect to the incident H⁺₂ for v ⩽ 1 and receed faster from the He atom than the H products. This observation directly leads to the conclusion that collision-induced dissociation from v = 0 and 1 involves transitions to the first excited potential-energy surface.     

Product rotational angular momentum polarization in the H+FCl(v=0-5, j=0, 3, 6, 9)→HF+Cl reaction

The product alignment and orientation of the title reaction on the ground potential energy surface of 1 (2)A' have been studied using the quasi-classical trajectory method. The calculations were carried out for case (a) at collision energies of 0.5-20 kcal mol(-1) with the initially rovibrational state of the reagent FCl molecule being at the v = 0 and j = 0 level to especially reveal in detail the dependence of the product integral cross section on collision energy. Further calculations at the collision energy of 15 kcal mol(-1) for case (b) at v = 0-5, and j = 0, and (c) at v = 0, and j = 3, 6, 9 initial states were carried out to reveal the effect of initially vibrational and rotational excitations on stereodynamics, respectively. Possessing final relative velocity k' (defined as a vector in the xz-plane), product alignment perpendicular to the reagent relative velocity vector k (defined as z- or parallel to the z-axis), for case (a) is found to be weaker at all collision energies, for case (b) is found to be vibrationally enhanced by the reactant molecule FCl, but for case (c), rather insensitive to initially rotational excitation. The rotational vector of product molecular orientation pointing to either negative or positive direction of the y-axis in the center of mass frame, e.g. origin of the coordinate system, is enhanced by collision energies regarding to 0.5-20 kcal mol(-1), while it becomes weaker at higher vibrational (v = 0-5) or rotational (j = 0, 3, 6, 9) excitation levels. Effects of collision energies and of rotational excitation at these collision energies, with 15 kcal mol(-1) as an example on the calculated PDDCSs are also shown and discussed. Detailed plots P(φ(r)) in the range of 0 ≤φ(r)≤ 360(o), and P(θ(r), φ(r)) in the ranges of 0 ≤θ(r)≤ 180° and 0 ≤φ(r)≤ 360° at collision energies 0.5-20 kcal mol(-1) have been presented. Overall, results of PDDCSs of the product alignment and product orientation at these collision energies in the title reaction are not very strongly distinguishable.     

Density functional study of S(N) 2 substitution reactions for CH(3) Cl + CX(1) X(2•-) (X(1) X(2) = HH, HF, HCl, HBr, HI, FF, ClCl, BrBr, and II)

A systematic investigation on the S_N2 displacement reactions of nine carbene radical anions toward the substrate CH₃Cl has been theoretically carried out using the popular density functional theory functional BHandHLYP level with different basis sets 6‐31+G (d, p)/relativistic effective core potential (RECP), 6‐311++G (d, p)/RECP, and aug‐cc‐pVTZ/RECP. The studied models are CX¹X^2?? + CH₃Cl → X²X¹CH₃C^? + Cl^?, with CX¹X^2?? = CH₂^??, CHF^??, CHCl^??, CHBr^??, CHI^??, CF₂^??, CCl₂^??, CBr₂^??, and CI₂^??. The main results are proposed as follows: (a) Based on natural bond orbital (NBO), proton affinity (PA), and ionization energy (IE) analysis, reactant CH₂^?? should be a strongest base among the anion‐containing species (CX¹X^2??) and so more favorable nucleophile. (b) Regardless of frontside attacking pathway or backside one, the S_N2 reaction starts at an identical precomplex whose formation with no barrier. (c) The back‐S_N2 pathway is much more preferred than the front‐S_N2 one in terms of the energy gaps [ΔE(front)?ΔE(back)], steric demand, NBO population analysis. Thus, the back‐S_N2 reaction was discussed in detail. On the one hand, based on the energy barriers (ΔE and ΔE) analysis, we have strongly affirmed that the stabilization of back attacking transition states (b‐TSs) presents increase in the order: b‐TS‐CI₂ < b‐TS‐CBr₂ < b‐TS‐CCl₂ < b‐TS‐CHI < b‐TS‐CHBr < b‐TS‐CHCl < b‐TS‐CF₂ < b‐TS‐CHF < b‐TS‐CH₂. On the other hand, depended on discussions of the correlations of ΔE with influence factors (PA, IE, bond order, and ΔE), we have explored how and to what extent they affect the reactions. Moreover, we have predicted that the less size of substitution (α‐atom) required for the gas‐phase reaction with α‐nucleophile is related to the α‐effect and estimated that the reaction with the stronger PA nucleophile, holding the lighter substituted atom, corresponds to the greater exothermicity given out from reactants to products. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012     

Structural, electronic, bonding, magnetic, and optical properties of bimetallic [Ru(n)Au(m)](0/+) (n + m ≤ 3) clusters

The structural, electronic, bonding, magnetic, and optical properties of bimetallic [Ru(n)Au(m)](0/+) (n + m ≤ 3; n, m = 0-3) clusters were computed in the framework of the density functional theory (DFT) and time-dependent DFT (TD-DFT) using the full-range PBE0 non local hybrid GGA functional combined with the Def2-QZVPP basis sets. Several low-lying states have been investigated and the stability of the ground state spinomers was estimated with respect to all possible fragmentation schemes. Molecular orbital and population analysis schemes along with computed electronic parameters illustrated the details of the bonding mechanisms in the [Ru(n)Au(m)](0/+) clusters. The TD-DFT computed UV-visible absorption spectra of the bimetallic clusters have been fully analyzed and compared to those of pure gold and ruthenium clusters. Assignments of all principal electronic transitions are given and interpreted in terms of contribution from specific molecular orbital excitations.