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1.
The partial potential energy surface of the I + HI →IH + I reaction involving the translational and vibrational motions has been constructed at the QCISD( T )//MP4SDQ level with the pseudo potential method that is helpful to interpreting the scattering resonance states. The lifetimes of the scattering resonance states in the title reaction obtained from the partial potential energy surface are about 90-120 fs, which agrees with the result of high-resolved threshold photodetachment spectroscopy of anion IHI^- measured by Neumark.  相似文献   

2.
Three-Coulomb-wave method is employed to treat the process of (e, 2e) simultaneous ion- ization and excitation to the n=2 state of helium, with radial and angular correlated wave-function of He target. The triple differential cross sections are calculated and analyzed in very asymmetric coplanar geometry at incident energies of 5.50, 1.50 and 0.57 keV. Results are compared with the absolute measurements and the theoretical first and second Born approximation. The present triply differential cross section (TDCS) is found to be in good agreement with experimental data qualitatively. The distinguishing feature noted in TDCS structure is the presence of intense recoil peak that for certain parameters is even larger than the binary peak, an unusual feature for the single-ionization process at high and intermediate energies.  相似文献   

3.
The partial potential energy surface(PPES) of Br+HBr(v=0)→BrH(v'=0)+Br was designed by coupling the vibration energy and the minimum energy of the corresponding reaction path, Vmep. All the calculations were performed at the theoritical level of QCISD(T)/6-311++G**//MP2/6-31 1++G**. Based on the analysis of PPES, the dynamic "Eyring Lake" mechanism gave birth to the scattering resonance state. The resonance energy was also obtained via PPES. Then a lifetime matrix of the resonance state was established by solving the translational wave-function via the numerical propagation method. Then the reaction resonance lifetime was calculated to be 125 fs. It is in good agreement with the experimental result.  相似文献   

4.
应用最近发展的价键组态相互作用(VBCI)方法计算了SN2反应Xl^- CH3Xr→XlCH3 Xr^-(X1=Xr=F,Cl,Br,I)的反应能垒和价键相关参数.计算结果表明.VBCI能垒与采用分子轨道理论的CCSD(T)方法计算的能垒相一致.讨沦了SN2反应的反应参数、  相似文献   

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The reaction of HCN with O(^1D, ^3p) radical has been investigated by density functional theory (DFT) and ab initio methods. The stationary points on the reaction paths (reactants, intermediates and products) were optimized at the (U)B3LYP/aug-cc-pVTZ level. Single-point calculations were performed at the (U)QCISD(T)/aug-cc-pVTZ level for the optimized structures and all the total energies were corrected by zero-point energy. It is shown that there exist three competing mechanisms of oxygen attacking nitrogen O→N, oxygen attacking carbon O→C and oxygen attacking hydrogen O→H. The rate constants were obtained via Eyring transition-state theory in the temperature range of 600~2000 K. The linear relationship between lnk and 1/T was presented. The results show that path 1 is the main reaction channel and the product of NCO + H is predominant.  相似文献   

7.
New global three dimensional potential energy surfaces for the Cl+H2 reactive system have been constructed using accurate multireference configuration interaction calculations with a large basis set. The three lowest adiabatic potential energy surfaces correlating asymptotically with Cl(^2p)+H2 have been transformed to adiabatic representation, which leads to a fourth coupling potential for non-linear geometries. In addition, the spin-orbit coupling surfaces have also been computed using the Breit-Pauli Hamiltonian. Properties of the new potential are described. Reaction dynamics based on the new potential agrees with the recent experimental results quite well.  相似文献   

8.
1 INTRODUCTION Interest in transition-metal sulfides arises from their significance in industrial catalysis and biolo- gy[1]. Transition-metal sulfides as versatile catalysts are often less susceptible to poisoning and show higher selectivity than their corresponding oxides[2]. In fact, the transition-metalion chemistry has been an active area for both experimental and theoretical studies[3~10]. Recently, Schwarz’s and Armentrout’s working groups[11, 12] have reported the experimenta…  相似文献   

9.
In order to study the Fe-Cu interactions and their effects on 31p NMR, the structures of mononuclear complex Fe(CO)3fPhzPpy)a 1 and binuclear complexes Fe(CO)3(PhEPpy)z(CuXn) (2: Xn = Cl2^2-, 3: Xn = Cl-, 4: Xn = Br-) are calculated by density functional theory (DFT) PBE0 method. For complexes 1, 3 and 4, the 31p NMR chemical shifts calculated by PBE0-GIAO method are in good agreement with experimental results. The 31p chemical shift is 82.10 ppm in the designed complex 2. The Fe-Cu interactions (including Fe→Cu and Fe←Cu charge transfer) mainly exhibit the indirect interactions. Moreover, the Fe-Cu(I) interactions (mostly acting as σFe-p→4Scu and aFe-C→4Scu charge transfer) in complexes 3 and 4 are stronger than Fe-Cu(Ⅱ) interactions (mostly acting as σFe-p→4Scu and σFe-p←4Sc,) in complex 2. In complex 2, the stronger Fe←Cu interac- tions, acting as σFe-p←44SCu charge transfer, increase the electron density on P nucleus, which causes the upfield 31p chemical shift compared with mononuclear complex 1. For 3 and 4, although a little deshielding for P nucleus is derived from the delocalization of σFe-p→4Scu due to the Fe→Cu interactions, the stronger σFe-c→np charge-transfer finally increases the electron density on P nucleus. As a result, an upfield 31p chemical shift is observed compared with 1. The stability follows the order of 2〉3=4, indicating that Fe(CO)3(PhzPpy)2(CuCl2) is stable and could be synthesized experimentally. The N-Cu(Ⅱ) interaction plays an important role in the stability of 2. Because the delocalization of σFe-p→4SCu and σFe-c→πc-o weakens the a bonds of Fe-C and ~r bonds of CO, it is favorable for increasing the catalytic activity of binuclear complexes. Complexes 3 and 4 are expected to show higher catalytic activity compared to 2.  相似文献   

10.
Theoretical studies of the dynamics of the reactions O(3p)+H2/HD(ν=0, j=0)→OH+H have been performed with quasi-classical trajectory method (QCT) on an ab initio potential surface for the lowest triplet electronic state of H2O(aA"). The QCT-calculated integral cross sections are in good agreement with the earlier time-dependent quantum mechanics results. The state-resolved rotational distributions reveal that the product OH rotational distributions for O+HD have a preference for populating highly internally excited states compared with the O+H2 reaction. Distributions of differential cross sections show that directions of scattering are strongly dependent on the choice of quantum state. The polarization dependent generalized differential cross-sections and the distributions were calculated and a pronounced isotopic effect is revealed. The calculated results indicate that the product polarization is very sensitive to the mass factor.  相似文献   

11.
(-)-7-Isopropyl-cis-1-amino-2-indanol, a key chiral auxiliary and ligand in the highly stereo-selective asymmetric 6π-azaelectrocyclization, has been prepared previously by two methods. Each however involved using of one extreme condition, i.e. high temperature or high pressure, for the respective reaction. A modified reaction route employed mild condition for synthesis was presented in this report.  相似文献   

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In the stratosphere,CF3Cl(CFC13)can either photodecompose or react directly with atomic oxygen to generate ozone-depleting agents such as Cl and ClO in the gas phase[1—3].Since the1970s,attention has been focused on the effects of these compounds on the …  相似文献   

15.
The reaction of a series of 1-(3-pyridyl)-2,2-di-substituted ethylenes with 1-benzyl-1,4-dihydronicotinamide (BNAH) in deaerated acetonitrile produces the corresponding 1-(3-pyridyl)-2,2-di-substituted ethanes in contrast to benzylidenemalononitrile (BM) which does not react with BNAH under the same conditions.  相似文献   

16.
The thermal behaviors of the complexes of Cu(DMTZB)4X2 (DMTZB=3,3‘-dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone, X=NO3 or ClO4) and Cu(DMTZB)2 X2 (X=Br or Cl) in a nitrogen atmosphere were studied under the non-isothermal conditions by simultaneous TG-DTG-DSC, EDS and elemental analysis techniques. The resuits showed that their decomposition proceeded in three different ways mainly depending on the anions in the molecules. The heat effect associated with the decomposition step of DMTZB molecules was also different. The decomposition mechanisms and the kinetic parameters of DMTZB were determined and calculated by jointly using four methods, which showed that its pyrolysis was controlled by D3 mechanism but with different activation energies and pre-exponential factors for different complexes.  相似文献   

17.
The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-(1 -x)K20] through thermodynamic properties. The calorimetric measurements were performed in HF solution calorimetry at 298 K. The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another. This thermodynamic non-ideality is caused by the slight variations of distance between metallic cations, the macromolecular structure being unchanged. It can be explained, at least qualitatively, using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hückel.  相似文献   

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