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1.
利用量子力学耦合通道扭曲波近似法(CCDWA)和三种势能面计算了H+H2碰撞的反应几率,结果发现在相同的势能面下利用CCDWA方法计算的反应几率和公认较好的计算结果符合很好,不同势能面共线势垒高度的差别将引起反应几率的不同.  相似文献   

2.
运用准经典轨线的方法,基于RODRIGO势能面,研究反应体系O++DH (v=0, j=0)→OD++H的立体动力学性质. 对描述k-j′两矢量相关和k-k′-j′三矢量相关的分布函数P(θr)和P(φr)以及产物转动取向参数进行了详细的讨论,发现极化微分反应截面呈现有趣的现象. 计算了反应几率与反应截面. O++DH (v=0, j=0)→OD++H反应的立体动力学性质对体系的碰撞能非常敏感.  相似文献   

3.
基于从头算势能面CH2(1A'),用准经典轨线(QCT)方法研究了不同振动激发(v=0-3)下反应H+CH→H2+C(1D)的动力学性质.在质心坐标系下计算了四个极化微分反应截面(PDDCDs),计算并讨论了描述k-j'矢量相关的P(θr)分布函数和描述k-k-'j'三矢量相关的二面角分布P(φr).研究结果表明势能面上的深势阱和不同的振动态对产物分子H2有重要影响.  相似文献   

4.
O(1D)+N2O→NO+NO反应的理论研究   总被引:3,自引:3,他引:0  
应用三体模型及扩展的LEPS势能面(PES),对初始条件为(Ecol=55 kJ/mol,v=0,j=0)的O(1D)+N2O→NO+NO反应体系进行了准经典轨线(QCT)计算.根据计算结果对体系的势能面及反应机理进行详细的分析和讨论,较全面地研究了此反应体系的动力学特征.  相似文献   

5.
运用多参考组态相互作用(MRCI)方法及aug-cc-pv5z基组构造了HeH+2体系基态(12A′)从头算势能面.采用多体展开法共拟合了8840个能量点,拟合误差为0.0677 Kcal/mol.基于新势能面,采用准经典轨线方法计算了碰撞能在0~2 eV范围内的积分反应截面,计算结果与实验结果符合较好.  相似文献   

6.
基于从头算势能面CH2 ,用准经典轨线(QCT)方法研究了不同振动激发(v=0-3)下反应H+CH→H2+C(1D)的动力学性质.在质心坐标系下计算了四个极化微分反应截面(PDDCDs),计算并讨论了描述 k- j''矢量相关的 分布函数和描述k- k-'' j''三矢量相关的二面角分布 。研究结果表明势能面上的深势阱和不同的振动态对产物分子H2有重要影响。  相似文献   

7.
基于Lv等人最新构建的高精度的最低三重态势能面H2S(3A″),利用准经典轨线(QCT)方法计算了H+HS反应的两个反应通道提取反应和交换反应的动力学性质.主要研究了在反应物HS的碰撞能为0.1-2.0 e V时,不同振转态(v=0-3,j=0-3)对积分反应截面和产物极化的影响.研究结果表明:在总角动量J=0时,QCT方法计算出的动力学结果和吕等人的量子力学(QM)结果符合的很好.因此,对标题反应的动力学性质进行了进一步的研究.  相似文献   

8.
采用准经典轨线方法[1,2]计算了碰撞能范围为0.6-1.2电子伏时反应He+HD+ (v=1,j=0, 1, 2, 3)→HeH++D和He+HD+ (v=1,j=0, 1, 2, 3)→HeD++H的积分截面。 通过跟有效的实验结果对比,发现计算结果略低于实验值,这可能是由于在计算中没有考虑量子效应而导致的。通过准经典轨线的计算结果与Tiwari等人的CS理论计算结果对比发现结果是基本相符合的,尤其是在几个碰撞能下几乎完全吻合。另外通过对比总结分析了 以及 势能面在不同的碰撞能以及不同的振转态下与CS理论计算的结果符合情况是的差异。同时重点分析了反应物的振转态对于反应的生成物以及积分截面的影响。  相似文献   

9.
报道了H原子和振动激发的HF(v=3,j=0)分子在低碰撞能下的量子反应动力学研究.计算结果表明:在低碰撞能下,散射主要以非反应过程为主;振动激发有利于反应的进行;在小于10-4eV碰撞能下,非反应非弹性散射截面和反应截面的比值约为3.在反应截面上发现了Feshbach共振现象,证实是由反应通道上紧邻反应势垒的H…HF(v=3,j=1~3)的范德瓦尔斯聚合体存在的准束缚态所形成.  相似文献   

10.
采用准经典轨线方法[1,2]计算了碰撞能范围为0.6~1.2电子伏时反应He+HD+ (v=1,j=0,1,2,3)→HeH++D和He+HD+ (v=1,j=0,1,2,3)→HeD++H的积分截面.通过跟有效的实验结果对比,发现计算结果略低于实验值,这可能是由于在计算中没有考虑量子效应而导致的.通过准经典轨线的计算结果与Tiwari等人的CS理论计算结果对比发现结果是基本相符合的,尤其是在几个碰撞能下几乎完全吻合.另外通过对比总结分析了V16以及V112势能面在不同的碰撞能以及不同的振转态下与CS理论计算的结果符合情况是的差异.同时重点分析了反应物的振转态对于反应的生成物以及积分截面的影响.  相似文献   

11.
The angular dependence of the polarization of neutrons from the reaction 3H(d, n)4He was measured at deuteron energies of 3.35, 4.35 and 5.35 MeV for reaction angles up to 165° lab. Polarization values were derived from the left-right asymmetry in n- scattering.  相似文献   

12.
The reaction 2H(d, pp)2n has been studied at a bombarding energy of 12 MeV, detecting the two protons in coincidence at angles of ±20° as well as +20° and −15°. In both cases, a narrow band was observed in a three-dimensional plot of the yield versus the energies of the two detected protons. E1 and E2, with most of the yield concentrated in the area where E1 ≈ E2. This suggests a two-step sequential process of the type d + d → (2p) + (2n) → p + p + n + n. In a missing mass plot for the third, undetected “particle” a pronounced, narrow peak appears at low relative energies in the (nn) system.  相似文献   

13.
The elastic d-d scattering near threshold is calculated with a resonating group method using exact deuteron wave functions evaluated from the Malfliet-Tjon two-nucleon potential. There is agreement with a recent experiment, where no evidence for a resonance near threshold has been found. This is supported also theoretically.  相似文献   

14.
The differential cross sections of 2H(d, d)2H, 2H(d, 3He)n, 2H(d, p)3H and 2H(d, t)p have been measured in a gas scattering chamber at ten bombarding energies between 2.0 and 6.2 MeV with accuracies ranging from ±1.7 % to ±3.4 %. The differential cross section of 2H(d, n)3He has been measured at forward angles to an accuracy of ±2.5 % at the same energies using a time-of-flight detection system. The neutron detection efficiency was calibrated from the 2H(d, 3He)n cross sections, so the neutron production cross sections reported here do not depend on any previous neutron measurements. The 2H(d, 3He)n cross sections have been converted into 2H(d, n) 3He cross sections and Legendre polynomial fits are given for the complete angular distributions of 2H(d, n)3He.  相似文献   

15.
Measurements of the abstraction reaction kinetics in the interaction of gaseous H atoms with D adsorbed on metal and semiconductor surfaces, H(g)+D(ad)/S→ products, have shown that the kinetics of the HD products are at variance with the expectations drawn from the operation of Eley–Rideal mechanisms. Furthermore, in addition to HD product molecules, D2 products were observed which are not expected in an Eley–Rideal scenario. Products and kinetics of abstraction reactions on Ni(100), Pt(111), and Cu(111) surfaces were recently explained by a random-walk model based solely on the operation of hot-atom mechanistic steps. Based on the same reaction scenario, the present work provides numerical solutions of the appropriate kinetic equations in the limit of the steady-state approximation for hot-atom species. It is shown that the HD and D2 product kinetics derived from global kinetic rate constants are the same as those obtained from local probabilities in the random walk model.

The rate constants of the hot-atom kinetics provide a background for the interpretation of measured data, which was missing up to now. Assuming that reconstruction affects the competition between hot-atom sticking and hot-atom reaction, the application of the present model at D abstraction from Cu(100) surfaces reproduces the essential characteristics of the experimentally determined kinetics.  相似文献   


16.
H atom densities are measured by threshold ionization mass spectrometry in a H2 parallel-plate RF discharge. Variations of H density near the surface in steady-state discharge conditions reveal different surface loss probabilities γ on stainless steel, hydrogenated amorphous silicon (a-Si:H) and oxidized silicon. Absolute γ values are obtained from time-resolved H density measurements in afterglow. The etching probability of Si per H atom incident on a-Si:H is also derived by monitoring SiH4 partial pressure and SiH(A2Δ) optical emission.  相似文献   

17.
Quasi-classical trajectory theory is used to study the reaction of O(3p) with H2 (D2) based on the ground 3A″ potential energy surface (PES). The reaction cross section of the reaction O+H2→+OH+H is in excellent agreement with the previous result. Vector correlations, product rotational alignment parameters (P2(j′. k)) and several polarizeddependent differential cross sections are further calculated for the reaction. The product polarization distribution exhibits different characteristics that can be ascribed to different motion paths on the PES, arising from various collision energies or mass factors.  相似文献   

18.
氢气-空气混合物中瞬态爆轰过程的二维数值模拟   总被引:12,自引:1,他引:11       下载免费PDF全文
 对高温火团引发的氢气-空气混合气的瞬态爆轰过程进行了二维数值模拟,考虑了H2-O2-N2的详细化学反应动力学机理,该机理包含了19个基元反应和9种组分。采用分裂格式处理带化学反应的Euler方程,其中使用全耦合的TVD格式求解流场,使用基于Gear算法的微分方程解法器求解化学反应过程。计算结果表明:在H2∶O2∶N2=0.4∶0.4∶0.2(摩尔比)的混合气中,高温气团初始温度为T/T0=5.3时可诱导爆轰,爆轰波以2 300 m/s的速度传播,同时爆轰波阵面在管壁会形成反射波。还对计算的爆轰波后组分的浓度和温度进行了讨论,为理解爆轰波后结构提供信息。  相似文献   

19.
杨学明  谢代前  张东辉 《物理》2006,35(6):443-446
化学反应共振态研究是化学动力学研究的重要前沿课题,对于理解基元化学反应的机理有重要的意义.本文中介绍了最近在这一研究方向的重大进展.通过对F+H2化学反应的全量子态分辨的分子束反应散射实验研究,观测到了F+H2中反应中明显的反应共振现象.通过高精度的全量子散射动力学研究,发现这一共振现象是由两个Feshbach共振态所引起的,而且这两个Feshbach共振态之间在前向散射有明显的量子干涉效应.这项研究工作使得我们对这一重要基元反应中的化学反应共振态研究向前迈进了一大步。  相似文献   

20.
A detailed effects of catalyst X (X?=?H2O, (H2O)2, NH3, NH3···H2O, H2O···NH3, HCOOH and H2SO4) on the HO4H → O3?+?H2O reaction have been investigated by using quantum chemical calculations and canonical vibrational transition state theory with small curvature tunnelling. The calculated results show that (H2O)2-catalysed reactions much faster than H2O-catalysed one because of the former bimolecular rate constant larger by 2.6–25.9 times than that of the latter one. In addition, the basic H2O···NH3 catalyst was found to be a better than the neutral catalyst of (H2O)2. However it is marginally less efficient than the acidic catalysts of HCOOH, and H2SO4. The effective rate constant (k't) in the presence of catalyst X have been assessed. It was found from k't that H2O (at 100% RH) completely dominates over all other catalysts within the temperature range of 280–320?K at 0?km altitude. However, compared with the rate constant of HO4H → H2O?+?O3 reaction, the k eff values for H2O catalysed reaction are smaller by 1–2 orders of magnitude, indicating that the catalytic effect of H2O makes a negligible contribution to the gas phase reaction of HO4H → O3?+?H2O.

Highlights

  • A detailed effects of catalyst of H2O, (H2O)2, NH3, NH3···H2O, H2O···NH3, HCOOH and H2SO4 on the HO4H → O3?+?H2O reaction has been performed.

  • From energetic viewpoint, H2SO4 exerts the strongest catalytic role in HO4H → O3?+?H2O reaction as compared with the other catalysts.

  • At 0 km altitude H2O (at 100% RH) completely dominates over all other catalysts within the temperature range of 280–320 K.

  • HO4H → H2O?+?O3 reaction with H2O cannot be compete with the reaction without catalyst, due to the fact that the effective rate constants in the presence of H2O are smaller.

  相似文献   

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