Faraday Discussions of The Chemical Society最新文献_第3页

Non-adiabatic reactive routes and the applicability of multiconfiguration time-dependent self-consistent field approximations 非绝热反应路径和多构型随时间自洽场近似的适用性

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100239

R. Kosloff, A. Hammerich

引用次数: 30

Exchange reactions of hydrogen atoms with SiD4: an inversion mechanism? 氢原子与SiD4的交换反应:反转机理?

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100073

B. Katz, Jeunghee Park, S. Satyapal, Shintaro Tasaki, A. Chattopadhyay, W. Yi, R. Bersohn

引用次数: 16

Ab initio molecular orbital and dynamics study of transition-state spectroscopy 从头算分子轨道和跃迁态光谱动力学研究

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100047

K. Yamashita, K. Morokuma

引用次数: 10

Dynamics of hydrogen adsorption on clean and alkali-metal covered Cu(110) 清洁和碱金属覆盖Cu吸附氢的动力学(110)

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100415

B. Hayden, C. Lamont

{"title":"Dynamics of hydrogen adsorption on clean and alkali-metal covered Cu(110)","authors":"B. Hayden, C. Lamont","doi":"10.1039/DC9919100415","DOIUrl":"https://doi.org/10.1039/DC9919100415","url":null,"abstract":"The activated dissociative adsorption of H2 and D2 on a clean Cu(110) and a Cu(110)-K(1 × 2) reconstructed surface has been studied using supersonic molecular beams. Enhanced sticking of H2 over D2 at any particular normal energy in the pure beam experiment on Cu(110) is interpreted as an indication of the importance of the vibrational coordinate in the dissociation dynamics. The relative contributions of vibrational and translational energy in accessing the barrier is separated in vibrationally hot, translationally cold seeded beams. Results for hydrogen are presented which indicate a translational onset for the first vibrationally excited state H2(v= 1) at 130 meV. This result is consistent with a theoretically predicted barrier to dissociation of ca. 700 meV which lies somewhat in the exit channel of a two-dimensional potential-energy surface (2D-PES). The effect of alkali-metal adsorption on the (1 × 2) reconstructed surface is shown to enhance hydrogen adsorption, increase the activation energy to desorption and reduce the activation energy to adsorption. This result is consistent with a reduction in the height of a late barrier caused by a deeper atomic potential in the ‘product’ region of the 2D-PES.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"64 1","pages":"415-423"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89174523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Transition-state control of product rotational distributions in H + RH → H2+ R reactions (RH = HCl, HBr, HI, CH4, C2H6, C3H8) H + RH→H2+ R反应(RH = HCl、HBr、HI、CH4、C2H6、C3H8)中产物旋转分布的过渡态控制

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100173

J. Valentini, P. Aker, G. Germann, Y. Huh

{"title":"Transition-state control of product rotational distributions in H + RH → H2+ R reactions (RH = HCl, HBr, HI, CH4, C2H6, C3H8)","authors":"J. Valentini, P. Aker, G. Germann, Y. Huh","doi":"10.1039/DC9919100173","DOIUrl":"https://doi.org/10.1039/DC9919100173","url":null,"abstract":"Measurements of the rotational state distributions for the H2 product of the H + RH → H2+ R reactions (RH = HCl, HBr, HI, CH4, C2H6, C3H8) at a collision energy of 1.6 eV are reported. For the reactions with the hydrogen halides we also have carried out quasiclassical trajectory calculations for conditions that mimic those of the experiments. We find that the rotational state distributions are quite characteristic and distinguishing in these systems. The combination of experiments and calculations allows us to provide some compelling explanation of how the structure and dynamics in the transition state are coupled to the product rotational state distributions. Not surprisingly, mere measurement of the rotational state distributions is insufficient to establish this connection, as illustrated by the results of the state-to-state experiments with the alkanes as reactants. These reactions give anomalous rotational state distributions, showing rotational excitation that actually increases with increasing product vibrational energy, rather than decreasing, as has been observed for all other reactions whose rotational and vibrational state distributions we know have been measured.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"10 1","pages":"173-182"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73806911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Resonances in heavy + light–heavy atom reactions: influence on differential and integral cross-sections and on transition-state photodetachment spectra 重+轻-重原子反应中的共振:对微分截面和积分截面以及过渡态光剥离光谱的影响

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100017

G. Schatz, D. Sokolovski, J. Connor

{"title":"Resonances in heavy + light–heavy atom reactions: influence on differential and integral cross-sections and on transition-state photodetachment spectra","authors":"G. Schatz, D. Sokolovski, J. Connor","doi":"10.1039/DC9919100017","DOIUrl":"https://doi.org/10.1039/DC9919100017","url":null,"abstract":"The effect of resonances on the observable properties of chemical reactions is studied theoretically, in particular for I + HI → IH + I and Cl + HCl → ClH + Cl. All of our calculations use hyperspherical coordinates and accurate coupled-channel solutions to the Schrodinger equation for reactive scattering in three dimensions. For I + HI, we investigate the effect of potential surface variation on transition-state IHI– photodetachment spectra for total angular momentum quantum number equal to zero. Four different I + HI London–Eyring–Polanyi–Sato (LEPS) surfaces are used, with classical barrier heights varying from 0.048 to 0.243 eV. The low-energy portion of the photodetachment spectra are examined in detail; it is found that peaks in the spectra arising from resonances and from direct scattering move up and broaden in energy as the barrier height is increased. An approximate match of the theoretical peak widths and spacings with the experimental ones is obtained for one of the surfaces. However, the peak intensities differ, suggesting that LEPS surfaces may not be adequate to characterize fully the observed spectra. For Cl + HCl, we perform a centrifugal-sudden hyperspherical calculation in order to examine the scattering properties of the single isolated resonance with transition-state quantum numbers (ν1, ν2, ν3)=(0, 0, 2)(where ν1= symmetric stretching, v2= bending, V3= asymmetric stretching quantum numbers). This relatively narrow (width 4 meV) resonance produces substantial peaks in certain state resolved reaction probabilities, which leads to a smooth step-like behaviour in the integral cross-sections, and Breit–Wigner (or Lorentzian) peaks in the differential cross-sections. Simple dynamical models are developed which explain these results.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"191 1","pages":"17-30"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76950628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 28

A new mechanism for absorption: collision-induced absorption 一种新的吸收机制:碰撞诱导吸收

Faraday Discussions of The Chemical Society Pub Date : 1991-01-01 DOI: 10.1039/DC9919100437

K. J. Maynard, A. D. Johnson, S. P. Daley, S. Ceyer

引用次数: 54

Metallic glasses in heterogeneous catalysis 金属玻璃在多相催化中的应用

Faraday Discussions of The Chemical Society Pub Date : 1990-07-24 DOI: 10.1039/DC9898700239

A. Baiker

引用次数: 182

Forces between non-ionic surfactant layers 非离子表面活性剂层之间的力

Faraday Discussions of The Chemical Society Pub Date : 1990-01-01 DOI: 10.1039/DC9909000129

P. Claesson, J. Eriksson, Christina E. Herder, B. Bergenståhl, E. Pezron, I. Pezron, P. Stenius

{"title":"Forces between non-ionic surfactant layers","authors":"P. Claesson, J. Eriksson, Christina E. Herder, B. Bergenståhl, E. Pezron, I. Pezron, P. Stenius","doi":"10.1039/DC9909000129","DOIUrl":"https://doi.org/10.1039/DC9909000129","url":null,"abstract":"The nature of the repulsive forces acting between non-ionic hydrophilic surfaces has been investigated by the surface-force technique. For that purpose the interactions between head-groups of several non-ionic surfactants adsorbed on mica or hydrophobed mica were measured. In addition, the swelling pressure between monoglyceride layers in both the lamellar and the gel phases was determined using a water vapour pressure method. Repulsive short-range forces with an effective range of 1–3 nm were observed. They are believed to result from a combination of hydration and steric effects. The temperature dependence of the short-range force depends on the type of non-ionic group. When ethylene oxide or dimethylphosphine oxide groups are exposed towards the aqueous phase, an increased temperature results in a thicker layer, a steeper repulsive force, and a stronger attractive minimum. On the other hand, the layer thickness and the force acting between surfaces with exposed dimethylamine oxide groups are largely temperature independent, whereas in the case of monopalmitin, the force is more repulsive at higher temperatures. This behaviour is discussed with respect to the phase relations in the corresponding surfactant–water phase diagrams.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"30 1","pages":"129-142"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75109012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

X-Ray absorption spectroscopy under conditions of total external reflection: application to the structural characterisation of the Cu/GaAs(100) interface 全外反射条件下的x射线吸收光谱:在Cu/GaAs(100)界面结构表征中的应用

Faraday Discussions of The Chemical Society Pub Date : 1990-01-01 DOI: 10.1039/DC9908900051

S. Pizzini, K. Roberts, G. Greaves, N. Barrett, I. S. Dring, R. Oldman

{"title":"X-Ray absorption spectroscopy under conditions of total external reflection: application to the structural characterisation of the Cu/GaAs(100) interface","authors":"S. Pizzini, K. Roberts, G. Greaves, N. Barrett, I. S. Dring, R. Oldman","doi":"10.1039/DC9908900051","DOIUrl":"https://doi.org/10.1039/DC9908900051","url":null,"abstract":"The theoretical principles and instrumentation requirements of X-ray absorption spectroscopy under conditions of total external reflection are described with particular reference to their application in the characterisation of solid/solid interfaces. The advantages of combining XANES, EXAFS and reflectivity in a single series of measurements are highlighted through the structural characterisation of oxide layers on Cu and GaAs(100). The data reveal the surface of Cu deposited on float-glass to comprise a macroscopic mix of metallic Cu and structurally disordered oxide. The latter appears to have a local structure close to that observed in Cu2O but with a higher oxygen coordination at the surface. The surface of commercial-grade GaAs(100) has ca. 7–9 A of disordered oxide in which Ga coordinates to oxygen both tetrahedrally and octahedrally whilst As is only found in tetrahedral sites. Strong correlated second-shell cation coordinations around both Ga and As central atoms reveal a single non-stoichiometric surface oxide depleted of As at the surface. 10 and 100 A thick Cu films deposited on GaAs(100) are found to be completely oxidised with the oxide being more disordered and having a higher oxygen coordination than those deposited on float-glass. For 10 A thick films, Cu appears coordinated to Ga and As through the oxygen which decorates the inner surfaces of micro-voids and fissures in the disordered oxide on GaAs.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"9 1","pages":"51-63"},"PeriodicalIF":0.0,"publicationDate":"1990-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87795523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8