We report the accurate determinations of quantum mechanical state-to-state probabilities tor reactions Cl + H2 - HCl + H and H' + HCl - H'Cl + H by the generalized Newton variational principle, on the most acc...We report the accurate determinations of quantum mechanical state-to-state probabilities tor reactions Cl + H2 - HCl + H and H' + HCl - H'Cl + H by the generalized Newton variational principle, on the most accurate available potential energy surface. We compare the results for three versions of realistic potential energy surfaces, and to those from hyperspherical close-coupling calculations.展开更多
A crossed molecular beams, state-to-state scattering study was carried out on the F＋H2→HF＋H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. ...A crossed molecular beams, state-to-state scattering study was carried out on the F＋H2→HF＋H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.展开更多
The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equatio...The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equation. This new propagator is exact and unconditionally convergent for calculating reactive scattering processes with large time step sizes. In order to improve the computational efficiency, the spectral difference method was applied. This resulted the Hamiltonian with elements confined in a narrow diagonal band. In contrast to our previous theoretical work, the discrete variable representation was applied and resulted in full Hamiltonian matrix. As examples, the collision energy-dependent probability of the triatomic H＋H2 and O＋O2 reaction are calculated. The numerical results demonstrate that this new propagator is numerically accurate and capable of propagating the wave packet with large time steps. However, the efficiency and accuracy of this new propagator strongly depend on the mathematical method for solving the involved linear equations and the choice of preconditioner.展开更多
Detailed understanding of the mechanism of the combustion relevant multichannel reactions of O(3P) with unsaturated hydrocarbons (UHs) requires the identification of all primary reaction products, the determination of...Detailed understanding of the mechanism of the combustion relevant multichannel reactions of O(3P) with unsaturated hydrocarbons (UHs) requires the identification of all primary reaction products, the determination of their branching ratios and assessment of intersystem crossing (ISC) between triplet and singlet potential energy surfaces (PESs). This can be best achieved combining crossed-molecular-beam (CMB) experiments with universal, soft ionization, mass-spectrometric detection and time-of-flight analysis to high-level ab initio electronic structure calculations of triplet/singlet PESs and RRKM/Master Equation computations of branching ratios (BRs) including ISC. This approach has been recently demonstrated to be successful for O(3P) reactions with the simplest UHs (alkynes, alkenes, dienes) containing two or three carbon atoms. Here, we extend the combined CMB/theoretical approach to the next member in the diene series containing four C atoms, namely 1,2-butadiene (methylallene) to explore how product distributions, branching ratios and ISC vary with increasing molecular complexity going from O(3P))+propadiene to O(3P)+1,2-butadiene. In particular, we focus on the most important, dominant molecular channels, those forming propene+CO (with branching ratio ∽0.5) and ethylidene+ketene (with branching ratio ∽0.15), that lead to chain termination, to be contrasted to radical forming channels (branching ratio ∽0.35) which lead to chain propagation in combustion systems.展开更多
Reaction resonance is a frontier topic in chemical dynamics research,and it is also essential to the understanding of mechanisms of elementary chemical reactions.This short article describes an im- portant development...Reaction resonance is a frontier topic in chemical dynamics research,and it is also essential to the understanding of mechanisms of elementary chemical reactions.This short article describes an im- portant development in the frontier of research.Experimental evidence of reaction resonance has been detected in a full quantum state resolved reactive scattering study of the F+H2 reaction.Highly accurate full quantum scattering theoretical modeling shows that the reaction resonance is caused by two Feshbach resonance states.Further studies show that quantum interference is present between the two resonance states for the forward scattering product.This study is a significant step forward in our understanding of chemical reaction resonance in the benchmark F+H2 system.Further experimental studies on the effect of H2 rotational excitation on dynamical resonance have been carried out.Dy- namical resonance in the F+H2(j=1)reaction has also been observed.展开更多
The similarity and dissimilarity of reactive scattering wave functions and molecular orbitalby linear combination of atomic orbitals(LCAOMO)are examined.Based on the similarity a method is pro-posed to construct the r...The similarity and dissimilarity of reactive scattering wave functions and molecular orbitalby linear combination of atomic orbitals(LCAOMO)are examined.Based on the similarity a method is pro-posed to construct the reactive scattering wave functions by linear combination of arrangement channel wavefunctions(LCACSW).Based on the dissimilarity,it is shown that the combination coefficients can be deter-mined by solving s set of simultaneous algebraic equations.The elements of the reactive scattering matrix areshown to be related to the combination coefficients of open arrangement channels.The differential and totalreactive scattering cross-section derived by this method agrees completely with that derived by other meth-ods.展开更多
Time dependent wave packet calculations have been performed for the H-+ H2nonreactive scattering, summed of elastic and inelastic probabilities, on the recent reported potential energy surface of the systems. The tota...Time dependent wave packet calculations have been performed for the H-+ H2nonreactive scattering, summed of elastic and inelastic probabilities, on the recent reported potential energy surface of the systems. The total probabilities for total angular momentum J up to 35 have been calculated to get the converged integral cross sections over collision energy range of 0.20 - 1.42 eV. Integral cross-sections and rate constants have been calculated from the wave packet transition probabilities for the initial states (υ = 0, j = 0) by means of J-shifting method and uniform J-shifting method for J > 0.展开更多
Quantum reactive scattering theory can describe quantum effects in chemical reaction processes such as tunneling, resonance and so on, while classical, semi-classical or qua-siclassical scattering theories cannot work...Quantum reactive scattering theory can describe quantum effects in chemical reaction processes such as tunneling, resonance and so on, while classical, semi-classical or qua-siclassical scattering theories cannot work. Quantum reactive scattering theory includes the close-coupled differential equation (CCDE) method and the algebra equation method. The former is very complicated; moreover, the matching work between transition展开更多
The dynamical Lie algebraic method is used to describe the quantum reactive scattering. For the collinear exchange reaction A+BC→AB+C, an analytical expression for the reactive transition probability, which involves ...The dynamical Lie algebraic method is used to describe the quantum reactive scattering. For the collinear exchange reaction A+BC→AB+C, an analytical expression for the reactive transition probability, which involves the main dynamic parameters of the system, is explicitly given. Numerical test calculations are carried out for the collinear reaction scattering H+H 2( n =0)→H 2( n ′=0)+H. The results show that the dynamical Lie algebraic method is very efficient for computing reaction probabilities.展开更多
The interatomic distances are used as coordinates for atom-diatom quantum reactivescattering. After mass scaling, coordinate rotation and transforming into hypersphericalcoordinates, the equation for quantum reactive ...The interatomic distances are used as coordinates for atom-diatom quantum reactivescattering. After mass scaling, coordinate rotation and transforming into hypersphericalcoordinates, the equation for quantum reactive scattering has a form similar to that forinelastic scattering. In this description, the chemical reactive system changes naturally anduniformly from the reactant state to the product state, no coordinate transformation betweendifferent arrangement channels being required.展开更多
文摘We report the accurate determinations of quantum mechanical state-to-state probabilities tor reactions Cl + H2 - HCl + H and H' + HCl - H'Cl + H by the generalized Newton variational principle, on the most accurate available potential energy surface. We compare the results for three versions of realistic potential energy surfaces, and to those from hyperspherical close-coupling calculations.
基金This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology and the National Natural Science Foundation of China.ACKN0WLEDGMENT This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology and the National Natural Science Foundation of China.
文摘A crossed molecular beams, state-to-state scattering study was carried out on the F＋H2→HF＋H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.
文摘The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equation. This new propagator is exact and unconditionally convergent for calculating reactive scattering processes with large time step sizes. In order to improve the computational efficiency, the spectral difference method was applied. This resulted the Hamiltonian with elements confined in a narrow diagonal band. In contrast to our previous theoretical work, the discrete variable representation was applied and resulted in full Hamiltonian matrix. As examples, the collision energy-dependent probability of the triatomic H＋H2 and O＋O2 reaction are calculated. The numerical results demonstrate that this new propagator is numerically accurate and capable of propagating the wave packet with large time steps. However, the efficiency and accuracy of this new propagator strongly depend on the mathematical method for solving the involved linear equations and the choice of preconditioner.
基金supported by “Fondazione Cassa Risparmio Perugia” (Project 2015.0331.021 Scientific & Technological Research)EC COST Action CM1404 (Chemistry of Smart Energy Carriers and Technologies– SMARTCATS)+1 种基金the Università degli Studi di Perugia (“Fondo Ricerca di Base 2017”)Italian MIUR and Università degli Studi di Perugia within the program“Department of Excellence-2018-2022-project AMIS”
文摘Detailed understanding of the mechanism of the combustion relevant multichannel reactions of O(3P) with unsaturated hydrocarbons (UHs) requires the identification of all primary reaction products, the determination of their branching ratios and assessment of intersystem crossing (ISC) between triplet and singlet potential energy surfaces (PESs). This can be best achieved combining crossed-molecular-beam (CMB) experiments with universal, soft ionization, mass-spectrometric detection and time-of-flight analysis to high-level ab initio electronic structure calculations of triplet/singlet PESs and RRKM/Master Equation computations of branching ratios (BRs) including ISC. This approach has been recently demonstrated to be successful for O(3P) reactions with the simplest UHs (alkynes, alkenes, dienes) containing two or three carbon atoms. Here, we extend the combined CMB/theoretical approach to the next member in the diene series containing four C atoms, namely 1,2-butadiene (methylallene) to explore how product distributions, branching ratios and ISC vary with increasing molecular complexity going from O(3P))+propadiene to O(3P)+1,2-butadiene. In particular, we focus on the most important, dominant molecular channels, those forming propene+CO (with branching ratio ∽0.5) and ethylidene+ketene (with branching ratio ∽0.15), that lead to chain termination, to be contrasted to radical forming channels (branching ratio ∽0.35) which lead to chain propagation in combustion systems.
基金Supported by the Chinese Academy of Sciences,the National Natural Science Foun-dation of China(Grant Nos.20328304,10574068,20533060 and 20525313)the Ministry of Science and Technology
文摘Reaction resonance is a frontier topic in chemical dynamics research,and it is also essential to the understanding of mechanisms of elementary chemical reactions.This short article describes an im- portant development in the frontier of research.Experimental evidence of reaction resonance has been detected in a full quantum state resolved reactive scattering study of the F+H2 reaction.Highly accurate full quantum scattering theoretical modeling shows that the reaction resonance is caused by two Feshbach resonance states.Further studies show that quantum interference is present between the two resonance states for the forward scattering product.This study is a significant step forward in our understanding of chemical reaction resonance in the benchmark F+H2 system.Further experimental studies on the effect of H2 rotational excitation on dynamical resonance have been carried out.Dy- namical resonance in the F+H2(j=1)reaction has also been observed.
基金the National Natural Science Foundation of China
文摘The similarity and dissimilarity of reactive scattering wave functions and molecular orbitalby linear combination of atomic orbitals(LCAOMO)are examined.Based on the similarity a method is pro-posed to construct the reactive scattering wave functions by linear combination of arrangement channel wavefunctions(LCACSW).Based on the dissimilarity,it is shown that the combination coefficients can be deter-mined by solving s set of simultaneous algebraic equations.The elements of the reactive scattering matrix areshown to be related to the combination coefficients of open arrangement channels.The differential and totalreactive scattering cross-section derived by this method agrees completely with that derived by other meth-ods.
文摘Time dependent wave packet calculations have been performed for the H-+ H2nonreactive scattering, summed of elastic and inelastic probabilities, on the recent reported potential energy surface of the systems. The total probabilities for total angular momentum J up to 35 have been calculated to get the converged integral cross sections over collision energy range of 0.20 - 1.42 eV. Integral cross-sections and rate constants have been calculated from the wave packet transition probabilities for the initial states (υ = 0, j = 0) by means of J-shifting method and uniform J-shifting method for J > 0.
文摘Quantum reactive scattering theory can describe quantum effects in chemical reaction processes such as tunneling, resonance and so on, while classical, semi-classical or qua-siclassical scattering theories cannot work. Quantum reactive scattering theory includes the close-coupled differential equation (CCDE) method and the algebra equation method. The former is very complicated; moreover, the matching work between transition
文摘The dynamical Lie algebraic method is used to describe the quantum reactive scattering. For the collinear exchange reaction A+BC→AB+C, an analytical expression for the reactive transition probability, which involves the main dynamic parameters of the system, is explicitly given. Numerical test calculations are carried out for the collinear reaction scattering H+H 2( n =0)→H 2( n ′=0)+H. The results show that the dynamical Lie algebraic method is very efficient for computing reaction probabilities.
基金Project supported by the National Natural Science Foundation of China.
文摘The interatomic distances are used as coordinates for atom-diatom quantum reactivescattering. After mass scaling, coordinate rotation and transforming into hypersphericalcoordinates, the equation for quantum reactive scattering has a form similar to that forinelastic scattering. In this description, the chemical reactive system changes naturally anduniformly from the reactant state to the product state, no coordinate transformation betweendifferent arrangement channels being required.
