Pub Date : 2021-01-01DOI: 10.1142/9789811228902_0012
I. Adamovič
50
50
{"title":"Solvation.","authors":"I. Adamovič","doi":"10.1142/9789811228902_0012","DOIUrl":"https://doi.org/10.1142/9789811228902_0012","url":null,"abstract":"50","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"158 1","pages":"1-399"},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73558250","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}
Pub Date : 2009-02-10DOI: 10.1039/9781847559319-00405
G. John, Thompson K. Clive
Physical state of di-nitrogen in the presence of porous solids probed by N spin-lattice relaxation in the 30 K – 300 K range. Is the nitrogen adsorption at 77 K usable for the characterization of microporous solids? J. Fraissard, S. Leclerc, W. Conner, D. Canet (1 LPEM-ESPCI-UPMC, 2 Univ. de Lorraine-LEMTA, 3 Univ. de Lorraine-ENSEM, France; 4 Univ. of Massachusetts, USA ; 5 Univ. de Lorraine, France)
在30k - 300k范围内，通过N自旋-晶格弛豫探测到多孔固体存在时双氮的物理状态。77k下的氮吸附是否可用于微孔固体的表征?J. Fraissard, S. Leclerc, W. Conner, D. Canet (1 LPEM-ESPCI-UPMC, 2洛林大学- lemta, 3洛林大学- ensem，法国;4马萨诸塞大学，美国;5洛林大学，法国)
{"title":"List of Posters","authors":"G. John, Thompson K. Clive","doi":"10.1039/9781847559319-00405","DOIUrl":"https://doi.org/10.1039/9781847559319-00405","url":null,"abstract":" Physical state of di-nitrogen in the presence of porous solids probed by N spin-lattice relaxation in the 30 K – 300 K range. Is the nitrogen adsorption at 77 K usable for the characterization of microporous solids? J. Fraissard, S. Leclerc, W. Conner, D. Canet (1 LPEM-ESPCI-UPMC, 2 Univ. de Lorraine-LEMTA, 3 Univ. de Lorraine-ENSEM, France; 4 Univ. of Massachusetts, USA ; 5 Univ. de Lorraine, France)","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"349 1","pages":"405-406"},"PeriodicalIF":0.0,"publicationDate":"2009-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74110152","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}
D. Chatfield, R. Friedman, D. Truhlar, D. Schwenke
It is shown that the accurate quantum-mechanical probability of the reaction of H with H2, with either zero or one unit of total angular momentum, increases with energy by increments of resolvable ‘quanta’ of reactive flux. These are analysed in terms of quantized transition states. Bend and stretch quantum numbers are assigned for total angular momentum J equal to zero and for both parities for J= 1 based on an analysis of the density of reactive states. A more detailed description of the reactive scattering process has been obtained by examining the state-selected densities of reactive states, and the initial H + H2 channels that contribute to the reactive flux passing through specific transition states have been determined.
{"title":"Quantum-dynamical characterization of reactive transition states","authors":"D. Chatfield, R. Friedman, D. Truhlar, D. Schwenke","doi":"10.1039/DC9919100289","DOIUrl":"https://doi.org/10.1039/DC9919100289","url":null,"abstract":"It is shown that the accurate quantum-mechanical probability of the reaction of H with H2, with either zero or one unit of total angular momentum, increases with energy by increments of resolvable ‘quanta’ of reactive flux. These are analysed in terms of quantized transition states. Bend and stretch quantum numbers are assigned for total angular momentum J equal to zero and for both parities for J= 1 based on an analysis of the density of reactive states. A more detailed description of the reactive scattering process has been obtained by examining the state-selected densities of reactive states, and the initial H + H2 channels that contribute to the reactive flux passing through specific transition states have been determined.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"22 1","pages":"289-304"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74629430","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}
The time evolution of the product energy distribution and product state coherence following the one photon excitation of a dissociating state of a molecule with one or two short pulses is a discussed qualitatively and illustrated with exact quantum calculations.
{"title":"Coherence and transients in photodissociation with short pulses","authors":"H. Metiu","doi":"10.1039/DC9919100249","DOIUrl":"https://doi.org/10.1039/DC9919100249","url":null,"abstract":"The time evolution of the product energy distribution and product state coherence following the one photon excitation of a dissociating state of a molecule with one or two short pulses is a discussed qualitatively and illustrated with exact quantum calculations.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"79 1","pages":"249-258"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88415381","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}
The relation of diffuse vibrational structures in UV-absorption spectra of (small) polyatomic molecules and internal vibrational motion in excited electronic states are investigated. The method of choice is the propagation of time-dependent wavepackets with the autocorrelation function serving as the link between the energy dependence of the spectrum and the time dependence of the molecular motion in the excited electronic state. For the purpose of this paper we characterize diffuse structures as very short-lived resonances with ‘lifetimes’ of the order of at most one internal vibrational period. In particular, we study a model system for the photodissociation of symmetric triatomic molecules ABA such as H2O, CO2 and O3, the photodissociation of H2O in the second continuum, and the fragmentation of H2S. The existence of unstable periodic orbits and their influence on the dissociation dynamics is especially elucidated. In the case of H2S we demonstrate that the diffuse absorption structures are caused by symmetric stretch motion in a binding state which is strongly coupled to a dissociative state. Diffuse structures can be regarded as very broad resonances in excited electronic states. They manifest transition-state spectroscopy in the original sense of the word.
{"title":"Diffuse structures and periodic orbits in the photodissociation of small polyatomic molecules","authors":"R. Schinke, K. Weide, B. Heumann, V. Engel","doi":"10.1039/DC9919100031","DOIUrl":"https://doi.org/10.1039/DC9919100031","url":null,"abstract":"The relation of diffuse vibrational structures in UV-absorption spectra of (small) polyatomic molecules and internal vibrational motion in excited electronic states are investigated. The method of choice is the propagation of time-dependent wavepackets with the autocorrelation function serving as the link between the energy dependence of the spectrum and the time dependence of the molecular motion in the excited electronic state. For the purpose of this paper we characterize diffuse structures as very short-lived resonances with ‘lifetimes’ of the order of at most one internal vibrational period. In particular, we study a model system for the photodissociation of symmetric triatomic molecules ABA such as H2O, CO2 and O3, the photodissociation of H2O in the second continuum, and the fragmentation of H2S. The existence of unstable periodic orbits and their influence on the dissociation dynamics is especially elucidated. In the case of H2S we demonstrate that the diffuse absorption structures are caused by symmetric stretch motion in a binding state which is strongly coupled to a dissociative state. Diffuse structures can be regarded as very broad resonances in excited electronic states. They manifest transition-state spectroscopy in the original sense of the word.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"70 1","pages":"31-46"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75130289","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}
The potential-energy surface of the excited-state reactions of calcium with halogen halides has been explored by the optical excitation of a Ca–HX van der Waals complex prepared in a supersonic expansion. Resonances and intense vibrational progressions of van der Waals modes have been observed, and the spectra have been analysed on a local-mode basis. It is seen that the excitation promotes modes involving the Ca–HCl bending coordinate, which appears to be different from the reaction coordinate.
{"title":"Observation of the reactive potential-energy surface of the Ca–HX* system through van der Waals excitation","authors":"B. Soep, C. J. Whitham, A. Keller, J. Visticot","doi":"10.1039/DC9919100191","DOIUrl":"https://doi.org/10.1039/DC9919100191","url":null,"abstract":"The potential-energy surface of the excited-state reactions of calcium with halogen halides has been explored by the optical excitation of a Ca–HX van der Waals complex prepared in a supersonic expansion. Resonances and intense vibrational progressions of van der Waals modes have been observed, and the spectra have been analysed on a local-mode basis. It is seen that the excitation promotes modes involving the Ca–HCl bending coordinate, which appears to be different from the reaction coordinate.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"32 1","pages":"191-205"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77762016","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}
Rotational alignment of the CO(X 1Σ+, v′= 14) product of the O(3P)+ CS(X 1Σ+) reaction has been measured relative to the velocity vector k of the reagents. O(3P) atoms were produced with k aligned in the laboratory frame by pulsed laser photolysis of NO2, and the CO product was detected by polarised laser-induced fluorescence. Transformation of the measured laboratory-frame rotational alignments to the required values of the alignment parameter 〈P2(J′·k)〉 were carried out using previously determined values of the translational anisotropy for the photodissociation of NO2, making allowances for both the thermal distribution of CS radicals and the spread of recoil energies of the O-atom fragment. Values of 〈P2(J′·k)〉 were measured for J′ between 12 and 35, and found to be close to zero to within the range 0 ± 0.25, with the mean value being slightly positive. Measurements of the Doppler profiles of the transitions are in qualitative agreement with those predicted for an isotropic distribution of product velocities about the k direction. These preliminary results illustrate the scope of laser based methods of extracting quantum-state-resolved data on scattering dynamics under experimental conditions which do not involve the use of molecular beam methods.
{"title":"Product rotational alignment for the reaction O(3P)+ CS(X 1Σ+)→ CO(X 1Σ+)+ S(3P)","authors":"F. Green, G. Hancock, A. Orr-Ewing","doi":"10.1039/DC9919100079","DOIUrl":"https://doi.org/10.1039/DC9919100079","url":null,"abstract":"Rotational alignment of the CO(X 1Σ+, v′= 14) product of the O(3P)+ CS(X 1Σ+) reaction has been measured relative to the velocity vector k of the reagents. O(3P) atoms were produced with k aligned in the laboratory frame by pulsed laser photolysis of NO2, and the CO product was detected by polarised laser-induced fluorescence. Transformation of the measured laboratory-frame rotational alignments to the required values of the alignment parameter 〈P2(J′·k)〉 were carried out using previously determined values of the translational anisotropy for the photodissociation of NO2, making allowances for both the thermal distribution of CS radicals and the spread of recoil energies of the O-atom fragment. Values of 〈P2(J′·k)〉 were measured for J′ between 12 and 35, and found to be close to zero to within the range 0 ± 0.25, with the mean value being slightly positive. Measurements of the Doppler profiles of the transitions are in qualitative agreement with those predicted for an isotropic distribution of product velocities about the k direction. These preliminary results illustrate the scope of laser based methods of extracting quantum-state-resolved data on scattering dynamics under experimental conditions which do not involve the use of molecular beam methods.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"90 1","pages":"79-90"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80336313","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}
The transition-state region of the F + H2, F + D2 and F + HD reactions has been studied by photoelectron spectroscopy of the negative ions FH–2, FD–2 and FDH–. Photodetachment of these anions can access three electronic states of the neutral, but transitions to the ground-state potential-energy surface for the reaction can be observed selectively by adjusting the polarization of the photodetachment laser. Under these conditions, the FH–2 spectrum is similar to the recent simulation by Zhang and Miller which used the T5a potential-energy surface for the F + H2 reaction. The spectra of all three isotopic anions are interpreted by comparison to previous reactive scattering calculations. This comparison strongly suggests that several of the peaks in the photoelectron spectra are due to transitions to scattering resonances.
{"title":"Negative-ion photodetachment as a probe of bimolecular transition states: the F + H2 reaction","authors":"A. Weaver, D. Neumark","doi":"10.1039/DC9919100005","DOIUrl":"https://doi.org/10.1039/DC9919100005","url":null,"abstract":"The transition-state region of the F + H2, F + D2 and F + HD reactions has been studied by photoelectron spectroscopy of the negative ions FH–2, FD–2 and FDH–. Photodetachment of these anions can access three electronic states of the neutral, but transitions to the ground-state potential-energy surface for the reaction can be observed selectively by adjusting the polarization of the photodetachment laser. Under these conditions, the FH–2 spectrum is similar to the recent simulation by Zhang and Miller which used the T5a potential-energy surface for the F + H2 reaction. The spectra of all three isotopic anions are interpreted by comparison to previous reactive scattering calculations. This comparison strongly suggests that several of the peaks in the photoelectron spectra are due to transitions to scattering resonances.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"51 1","pages":"5-16"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78725476","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}
Photofragment mapping and 18O isotopic labelling have been used to probe the character of the transition state for the predissociation channels HCO2H(A1A″)→ HCO(X 2A′)+ OH(X 2Π) in jet-cooled, vibronically state selected formic acid, and the nature of the vibronic states initially accessed in the Franck–Condon region. The dynamics on the excited potential-energy surface are compared with those in the isoelectronic molecule HONO(A1A″). Almost all the available energy above the dissociation limit is concentrated into fragment recoil, regardless of the initial vibronic state selection: the experimental data indicate a substantial, late exit barrier and trajectories funnelled through a near collinear HO—C—O structure at the transition state.
{"title":"State-to-state photodissociation dynamics in formic acid","authors":"M. Brouard, J. Simons, J.‐X. Wang","doi":"10.1039/DC9919100063","DOIUrl":"https://doi.org/10.1039/DC9919100063","url":null,"abstract":"Photofragment mapping and 18O isotopic labelling have been used to probe the character of the transition state for the predissociation channels HCO2H(A1A″)→ HCO(X 2A′)+ OH(X 2Π) in jet-cooled, vibronically state selected formic acid, and the nature of the vibronic states initially accessed in the Franck–Condon region. The dynamics on the excited potential-energy surface are compared with those in the isoelectronic molecule HONO(A1A″). Almost all the available energy above the dissociation limit is concentrated into fragment recoil, regardless of the initial vibronic state selection: the experimental data indicate a substantial, late exit barrier and trajectories funnelled through a near collinear HO—C—O structure at the transition state.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"28 1","pages":"63-72"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78758629","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}
A theory of the laser catalysis of the H + H2 exchange reaction in the collinear configuration and in three dimensions is presented. The collinear H + H2 system in a strong laser field is treated by a method composed of a converged coupled channels expansion for the non-radiative processes, coupled with an exact partitioning technique for the interaction with the radiation. The method enables computations to be performed for an arbitrary number of field-intensities with very little effort beyond that required for a single-intensity computation.By studying the optical reactive line-shapes as a function of the scattering energy, the signature of the scattering resonances on optically induced reaction is unravelled. It is shown that when the collision energy is tuned to a resonance, laser catalysis results in selective vibrational excitation of the product H2 molecule. Implications of this effect for past and future experiments are discussed.A three-dimensional theory based on the same exact partitioning technique is then presented. In this case, the bound–free scattering amplitudes, which serve as input to the theory, are obtained by assuming separability in terms of a hindered-rotor vibrationally adiabatic basis. We use the theory to compute reactive differential and integral laser-catalysis cross-sections. We study the laser intensity dependence of the reactivity, the role played by isolated and overlapping power-broadened resonances and how the angle of the relative velocities of the reagents affects the reactivity.
{"title":"Quantum theory of laser catalysis in one and three dimensions","authors":"T. Seideman, J. Krause, M. Shapiro","doi":"10.1039/DC9919100271","DOIUrl":"https://doi.org/10.1039/DC9919100271","url":null,"abstract":"A theory of the laser catalysis of the H + H2 exchange reaction in the collinear configuration and in three dimensions is presented. The collinear H + H2 system in a strong laser field is treated by a method composed of a converged coupled channels expansion for the non-radiative processes, coupled with an exact partitioning technique for the interaction with the radiation. The method enables computations to be performed for an arbitrary number of field-intensities with very little effort beyond that required for a single-intensity computation.By studying the optical reactive line-shapes as a function of the scattering energy, the signature of the scattering resonances on optically induced reaction is unravelled. It is shown that when the collision energy is tuned to a resonance, laser catalysis results in selective vibrational excitation of the product H2 molecule. Implications of this effect for past and future experiments are discussed.A three-dimensional theory based on the same exact partitioning technique is then presented. In this case, the bound–free scattering amplitudes, which serve as input to the theory, are obtained by assuming separability in terms of a hindered-rotor vibrationally adiabatic basis. We use the theory to compute reactive differential and integral laser-catalysis cross-sections. We study the laser intensity dependence of the reactivity, the role played by isolated and overlapping power-broadened resonances and how the angle of the relative velocities of the reagents affects the reactivity.","PeriodicalId":12210,"journal":{"name":"Faraday Discussions of The Chemical Society","volume":"4 1","pages":"271-288"},"PeriodicalIF":0.0,"publicationDate":"1991-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85600704","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}
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