Bai Meng-Meng, Ge Mei-Hua, Yang Huan, and Zheng Yu-Jun School of Physics, Shandong University, J/nan 250100, China The quasi-classical trajectory （QCT） method is used to study the H＋HS reaction on a newly built pot...Bai Meng-Meng, Ge Mei-Hua, Yang Huan, and Zheng Yu-Jun School of Physics, Shandong University, J/nan 250100, China The quasi-classical trajectory （QCT） method is used to study the H＋HS reaction on a newly built potential energy surface （PES） of the triplet state of H2S （3AH） in a collision energy range of 0-60 kcal/mol. Both scalar properties, such as the reaction probability and the integral cross section （ICS）, and the vector properties, such as the angular distribution between the relative velocity vector of the reactant and that of the product, etc., are investigated using the QCT method. It is found that the ICSs obtained by the QCT method and the quantum mechanical （QM） method accord well with each other. In addition, the distribution for the product vibrational states is cold, while that for the product rotational states is hot for both reaction channels in the whole energy range studied here.展开更多
Dynamics of the Au + H2 reaction are studied using time-dependent wave packet(TDWP) and quasi-classical trajectory(QCT) methods based on a new potential energy surface [Int. J. Quantum Chem. 118 e25493(2018)]. The dyn...Dynamics of the Au + H2 reaction are studied using time-dependent wave packet(TDWP) and quasi-classical trajectory(QCT) methods based on a new potential energy surface [Int. J. Quantum Chem. 118 e25493(2018)]. The dynamic properties such as reaction probability, integral cross section, differential cross section and the distribution of product are studied at state-to-state level of theory. Furthermore, the present results are compared with the theoretical studies available.The results indicate that the complex-forming reaction mechanism is dominated in the reaction in the low collision energy region and the abstract reaction mechanism plays a dominant role at high collision energies. Different from previous theoretical calculations, the side-ways scattering signals are found in the present work and become more and more apparent with increasing collision energy.展开更多
Quasi-classical trajectory （QCT） calculations are employed to study the dynamic properties for H（D）＋OF reactions on the adiabatic potential energy surface （PES） of the 1^3A″ triplet state. Obvious differences ...Quasi-classical trajectory （QCT） calculations are employed to study the dynamic properties for H（D）＋OF reactions on the adiabatic potential energy surface （PES） of the 1^3A″ triplet state. Obvious differences between the reaction probabilities for J=0, integral cross sections for J≠0, branch ratios of the product and internuclear distances as well as product rotational alignments between the title reactions axe found. These differences are attributed mainly to the different reduced masses of the reactants and the different zero-point energies （ZPEs） of the transition state.展开更多
The quasi-classical trajectory calculations O＋＋DH（v=0,j=0）→OD＋＋H reactions on the RODRIGO potential energy surface have been carried out to study the isotope effect on stereo-dynamics at the collision energies ...The quasi-classical trajectory calculations O＋＋DH（v=0,j=0）→OD＋＋H reactions on the RODRIGO potential energy surface have been carried out to study the isotope effect on stereo-dynamics at the collision energies of 1.0, 1.5, 2.0, and 2.5 eV. The distributions of dihedral angle P（~r） and the distributions of P（Or） are discussed. Furthermore, the angular distributions of the product rotational vectors in the form of polar plot in θr and φr are calculated. The differential cross section shows interesting phenomenon that the reaction is dominated by the direct reaction mechanism. Reaction probability and reaction cross section are also calculated. The calculations indicate that the stereo-dynamics properties of the title reactions are sensitive to the collision energy.展开更多
Quasi-classical trajectory calculations have been employed to investigate the influence of collision energy on the stereodynamics of the title reaction C＋CD--~C2＋D on the poten- tial energy surface of the 12AI state...Quasi-classical trajectory calculations have been employed to investigate the influence of collision energy on the stereodynamics of the title reaction C＋CD--~C2＋D on the poten- tial energy surface of the 12AI state developed by Boggio-Pasqua et al. [Mol. Phys. 98, 1925 （2000）]. The product angular distributions which reflect the vector correlation have been calculated. In addition, two polarization-dependent different cross-sections are also presented in the center-of-mass frame respectively. The results indicate that the product C2 is sensitively affected by collision energy.展开更多
The Ca＋CH3I→CaI＋CH3 reaction system has been studied with the quasi-classical trajectory method on the extended Lond-Eyring-Polanyi-Sato（LEPS） potential energy surface. At collision energy Ecol=10.78 kJ/mol, the ...The Ca＋CH3I→CaI＋CH3 reaction system has been studied with the quasi-classical trajectory method on the extended Lond-Eyring-Polanyi-Sato（LEPS） potential energy surface. At collision energy Ecol=10.78 kJ/mol, the calculated results show that the CaI vibrational population peaks are located at v=2. The calculated cross section decreases slowly with the collision energy increasing. The angle product distributions tend toward backward scattering. The calculated （P2（J^1·K）） values deviate slightly from-0.5 and decrease with increasing collision energy. The Quasiclassical trajectory calculation（QCT） results are in reasonable agreement with experimental data. Moreover, the dynamics of the reaction has been discussed.展开更多
The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory （QCT） method on the 11At potential energy surface at a collision energy of 23.06 kcal/mol. The...The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory （QCT） method on the 11At potential energy surface at a collision energy of 23.06 kcal/mol. The angular distributions P（φr ）, P（θr）, P（θr, φr）, and the polarization-dependent generalized differential cross sections are calculated, which demonstrate the observable influences on the rotational polarization of the product by the isotopic substitution of H with D.展开更多
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 elect...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.展开更多
We have carried out a quasi-classical trajectory calculation for the reaction ofNe ＋ H2＋ （v = 0, j = 1） → NeH＋ ＋ H on the ground state （12AI） using the LZHH potential energy surface constructed by L/i et al. ...We have carried out a quasi-classical trajectory calculation for the reaction ofNe ＋ H2＋ （v = 0, j = 1） → NeH＋ ＋ H on the ground state （12AI） using the LZHH potential energy surface constructed by L/i et al. [Lu S J, Zhang P Y, Han K L and He G Z 2010 J. Chem. Phys. 132 014303]. Differential cross sections at many collision energies indicate that the reaction is dominated by forward-scattering. In addition, the Nell＋ product shows rotationally hot and vibrationally cold distributions. Stereodynamical results indicate that the products are strongly polarized in the direction perpendicular to the scattering plane and that the products rotate mainly in planes parallel to the scattering plane.展开更多
Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a t...Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a three-impulse contingency return trajectory scheme is presented by combining the Lambert transfer and maneuver at the special point.Secondly,a calculation model of three-impulse contingency return trajectories is established.Then,fast calculation methods are proposed by adopting the high-order Taylor expansion of differential algebra in the twobody trajectory dynamics model and perturbed trajectory dynamics model.Finally,the performance of the proposed methods is verified by numerical simulation.The results indicate that the fast calculation method of two-body trajectory has higher calculation efficiency compared to the semi-analytical calculation method under a certain accuracy condition.Due to its high efficiency,the characteristics of the three-impulse contingency return trajectories under different contingency scenarios are further analyzed expeditiously.These findings can be used for the design of contingency return trajectories in future manned lunar landing missions.展开更多
Quasi-classical trajectory(QCT)calculations are reported for the H+LiH(v=0-2,j=0)→Li+H2 reaction on a new ground electronic state global potential energy surface(PES)of the LiH2 system.Reaction probability and integr...Quasi-classical trajectory(QCT)calculations are reported for the H+LiH(v=0-2,j=0)→Li+H2 reaction on a new ground electronic state global potential energy surface(PES)of the LiH2 system.Reaction probability and integral cross sections(ICSs)are calculated for collision energies in the range of 0 eV-0.5 eV.Reasonable agreement is found in the comparison between present results and previous available theoretical results.We carried out statistical analyses with all the trajectories and found two main distinct reaction mechanisms in the collision process,in which the stripping mechanism(i.e.,without roaming process)is dominated over the collision energy range.The polarization dependent differential cross sections(PDDCSs)indicate that forward scattering dominates the reaction due to the dominated mechanism.Furthermore,the reactant vibration leads to a reduction of the reactivity because of the barrierless and attractive features of PES and mass combination of the system.展开更多
The stereodynamic properties of the F+HO(v,j)reaction are explored by quasi-classical trajectory(QCT)calculations performed on the 1At and 3At potential energy surfaces(PESs).Based on the polarization-dependent differ...The stereodynamic properties of the F+HO(v,j)reaction are explored by quasi-classical trajectory(QCT)calculations performed on the 1At and 3At potential energy surfaces(PESs).Based on the polarization-dependent differential cross sections(PDDCSs)and the angular distributions of the product angular momentum with the reactant at different values of initial v or j,the results show that the product scattering and product polarization have strong links with initial vibrationalrotational numbers of v and j.The significant manifestation of the normal DCSs is that the forward scattering gradually becomes predominant with the initial vibrational excitation increasing,and the scattering angle of the HF product taking place on the 3At potential energy surface is found to be more sensitive to the initial value of v.The product orientation and alignment are strongly dependent on the initial rovibrational excitation effect.With enhancement in the initial rovibrational excitation effect,there is an overall decrease in the product orientation as well as in the product alignment either perpendicular to the reagent relative velocity vector k or along the direction of the y axis,for which the initial rotational excitation effect is much more noticeable than the vibrational excitation effect.Moreover,the initial rovibrational excitation effect on the product polarization is more pronounced for the 3At potential energy surface than for the 1At potential energy surface.展开更多
The vector properties of reaction O（1D）＋HBr→OH＋Br on the potential energy surface （PES） of X1A＇ ground singlet state are studied by using the quasi-classical trajectory （QCT） theory. The polarization-depende...The vector properties of reaction O（1D）＋HBr→OH＋Br on the potential energy surface （PES） of X1A＇ ground singlet state are studied by using the quasi-classical trajectory （QCT） theory. The polarization-dependent differential cross sections （PDDCSs）, the average rotational alignment factor （P 2 （j＇- k）〉, as well as the distributions reflecting vector correlations are also computed. The analysis of the results shows that the alignment and the orientation distribution of the rotation angular momentum vector of product molecule OH is influenced by both the effect of heavy-light heavy （HLH） type mass combination and the deep well of PES.展开更多
Quasi-classical trajectory （QCT） studies on the stereodynamics of H ＋ BrO → O＋ HBr reaction have been performed on the X1A＇ state of ab initio potential energy surface by Peterson [Peterson K A 2000 J. Chem. Phy...Quasi-classical trajectory （QCT） studies on the stereodynamics of H ＋ BrO → O＋ HBr reaction have been performed on the X1A＇ state of ab initio potential energy surface by Peterson [Peterson K A 2000 J. Chem. Phys. 113 4598] in a collision energy range from 0 kcal/mol to 6 kcal/mol. Two of the polarization-dependent generalized differential cross sections （PDDCSs）, （2π/σ）（dσ 00/d ω） （PDDCSoo） and （2π/σ）（dσ20/doh） （PDDCS20） are considered. The rotational polarizations of these products show sensitive behaviors to the calculated collision energy range. Furthermore, in order to gain more knowledge about vector correlations, the product angular distribution, P（θr）, and the dihedral angle, P （Фr）, are calculated, and the results indicate that both the rotational alignment and orientation of the product are enhanced as collision energy increases.展开更多
The reaction H+SO_(2)→OH+SO is important in the combustion and atmospheric chemistry,as well as the interstellar medium.It also represents a typical complex-forming reaction with deep complexes,serving as an ideal ca...The reaction H+SO_(2)→OH+SO is important in the combustion and atmospheric chemistry,as well as the interstellar medium.It also represents a typical complex-forming reaction with deep complexes,serving as an ideal candidate for testing various kinetics theories and providing interesting reaction dynamical phenomena.In this work,we reported a quasiclassical trajectory study of this reaction on our previously developed accurate full-dimensional potential energy surface.The experimental thermal rate coefficients over the temperature range 1400 K≤T≤2200 K were well reproduced.For the reactant SO_(2)being sampled at the ground ro-vibrational state,the calculated integral cross sections increased slightly along the collision energy ranging from 31.0 kcal/mol to 40.0 kcal/mol,and then became essentially flat at the collision energy within 40.0−55.0 kcal/mol.The product angular distributions are almost symmetric with nearly identical backward-forward double peak structure.The products OH and SO vibrational state distributions were also analyzed.展开更多
A quasi-classical trajectory study of the H(^(2)S)+NO(X^(2)Π)→N(^(4)S)+OH(X^(2)Π) reaction kinetics and dynamics is reported on an accurate potential energy surface.The total integral cross sections of the reaction...A quasi-classical trajectory study of the H(^(2)S)+NO(X^(2)Π)→N(^(4)S)+OH(X^(2)Π) reaction kinetics and dynamics is reported on an accurate potential energy surface.The total integral cross sections of the reaction were calculated at the collision energy ranging from 2.00 e V to 2.80 e V.It was found that the total reaction integral cross section increases monotonically with the collision energy.Specifically at the collision energy range of 2.40-2.57 e V,our calculated results are in reasonably good agreement with the experimental data.The calculated thermal rate constants are in fairly good agreement with available experimental results.Through the trajectory analysis at the collision energy of 2.57 e V,it was found that the title reaction is dominated by the indirect trajectories(1.4 times more compared to the direct trajectories),which sheds light on the reaction dynamics of the title reaction in the high collision energy range.展开更多
In this paper, the stereodynamics of Li ＋ DF → Li F ＋ D reaction is investigated by the quasi-classical trajectory（QCT）method on the ^2A＇ potential energy surface（PES） at a relatively low collision energy of 8...In this paper, the stereodynamics of Li ＋ DF → Li F ＋ D reaction is investigated by the quasi-classical trajectory（QCT）method on the ^2A＇ potential energy surface（PES） at a relatively low collision energy of 8.76 kcal/mol. The scalar properties of the title reaction such as reaction probability and cross section are studied with vibrational quantum number of v = 1–6. The product angular distributions P（θr） and P（φr） are presented in the same vibrational level range. Moreover, two polarization-dependent generalized differential cross sections（PDDCSs）, i.e., the PDDCS00 and PDDCS22＋are calculated as well. These stereodynamical results demonstrate sensitive behaviors to the vibrational quantum numbers.展开更多
The principle of direct method used in optimal control problem is introduced. Details of applying this method to flight trajectory generation are presented including calculation of velocity and controls histories. And...The principle of direct method used in optimal control problem is introduced. Details of applying this method to flight trajectory generation are presented including calculation of velocity and controls histories. And capabilities of flight and propulsion systems are considered also. Combined with digital terrain map technique, the direct method is applied to the three dimensional trajectory optimization for low altitude penetration, and simplex algorithm is used to solve the parameters in optimization. For the small number of parameters, the trajectory can be optimized in real time on board.展开更多
In view of generating optimal trajectories of Bolza problems, standard Chebyshev pseudospectral （PS） method makes the points＇ accumulation near the extremities and rarefaction of nodes close to the center of interv...In view of generating optimal trajectories of Bolza problems, standard Chebyshev pseudospectral （PS） method makes the points＇ accumulation near the extremities and rarefaction of nodes close to the center of interval, which causes an ill-condition of differentiation matrix and an oscillation of the optimal solution. For improvement upon the difficulties, a mapped Chebyshev pseudospectral method is proposed. A conformal map is applied to Chebyshev points to move the points closer to equidistant nodes. Condition number and spectral radius of differentiation matrices from both methods are presented to show the improvement. Furthermore, the modification keeps the Chebyshev pseudospectral method＇s advantage, the spectral convergence rate. Based on three numerical examples, a comparison of the execution time, convergence and accuracy is presented among the standard Chebyshev pseudospectral method, other collocation methods and the proposed one. In one example, the error of results from mapped Chebyshev pseudospectral method is reduced to 5% of that from standard Chebyshev pseudospectral method.展开更多
Aiming at increasing the calculation efficiency of the pseudospectral methods, a multiple- interval Radau pseudospectral method （RPM） is presented to generate a reusable launch vehicle （RLV） ＇s optimal re-entry t...Aiming at increasing the calculation efficiency of the pseudospectral methods, a multiple- interval Radau pseudospectral method （RPM） is presented to generate a reusable launch vehicle （RLV） ＇s optimal re-entry trajectory. After dividing the optimal control problem into many intervals, the state and control variables are approximated using many fixed- and low-degree Lagrange polyno- mials in each interval. Convergence of the numerical discretization is then achieved by increasing the number of intervals. With the application of the proposed method, the normal nonlinear program- ming （NLP） problem transcribed from the optimal control problem can avoid being dense because of the low-degree approximation polynomials in each interval. Thus, the NLP solver can easily compute a solution. Finally, simulation results show that the optimized re-entry trajectories satisfy the path constraints and the boundary constraints successfully. Compared with the single interval RPM, the multiple-interval RPM is significantly faster and has higher calculation efficiency. The results indicate that the multiple-interval RPM can be applied for real-time trajectory generation due to its high effi- ciency and high precision.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.21073110)the Independent Innovation Foundation of Shandong University,China(Grant No.2010GN030)the National Science Foundation for Postdoctoral Scientists of China(Grant No.20100481280)
文摘Bai Meng-Meng, Ge Mei-Hua, Yang Huan, and Zheng Yu-Jun School of Physics, Shandong University, J/nan 250100, China The quasi-classical trajectory （QCT） method is used to study the H＋HS reaction on a newly built potential energy surface （PES） of the triplet state of H2S （3AH） in a collision energy range of 0-60 kcal/mol. Both scalar properties, such as the reaction probability and the integral cross section （ICS）, and the vector properties, such as the angular distribution between the relative velocity vector of the reactant and that of the product, etc., are investigated using the QCT method. It is found that the ICSs obtained by the QCT method and the quantum mechanical （QM） method accord well with each other. In addition, the distribution for the product vibrational states is cold, while that for the product rotational states is hot for both reaction channels in the whole energy range studied here.
文摘Dynamics of the Au + H2 reaction are studied using time-dependent wave packet(TDWP) and quasi-classical trajectory(QCT) methods based on a new potential energy surface [Int. J. Quantum Chem. 118 e25493(2018)]. The dynamic properties such as reaction probability, integral cross section, differential cross section and the distribution of product are studied at state-to-state level of theory. Furthermore, the present results are compared with the theoretical studies available.The results indicate that the complex-forming reaction mechanism is dominated in the reaction in the low collision energy region and the abstract reaction mechanism plays a dominant role at high collision energies. Different from previous theoretical calculations, the side-ways scattering signals are found in the present work and become more and more apparent with increasing collision energy.
基金Project supported by the National Natural Science Foundation of China (Grant No.10574083)the Natural Science Foundation of Shandong Province of China (Grant No.Y2006A23)+1 种基金the National Basic Research Program of China (Grant No.2006CB806000)the Open Fund of the State Key Laboratory of High Field Laser Physics (Shanghai Institute of Optics and Fine Mechanics)
文摘Quasi-classical trajectory （QCT） calculations are employed to study the dynamic properties for H（D）＋OF reactions on the adiabatic potential energy surface （PES） of the 1^3A″ triplet state. Obvious differences between the reaction probabilities for J=0, integral cross sections for J≠0, branch ratios of the product and internuclear distances as well as product rotational alignments between the title reactions axe found. These differences are attributed mainly to the different reduced masses of the reactants and the different zero-point energies （ZPEs） of the transition state.
文摘The quasi-classical trajectory calculations O＋＋DH（v=0,j=0）→OD＋＋H reactions on the RODRIGO potential energy surface have been carried out to study the isotope effect on stereo-dynamics at the collision energies of 1.0, 1.5, 2.0, and 2.5 eV. The distributions of dihedral angle P（~r） and the distributions of P（Or） are discussed. Furthermore, the angular distributions of the product rotational vectors in the form of polar plot in θr and φr are calculated. The differential cross section shows interesting phenomenon that the reaction is dominated by the direct reaction mechanism. Reaction probability and reaction cross section are also calculated. The calculations indicate that the stereo-dynamics properties of the title reactions are sensitive to the collision energy.
文摘Quasi-classical trajectory calculations have been employed to investigate the influence of collision energy on the stereodynamics of the title reaction C＋CD--~C2＋D on the poten- tial energy surface of the 12AI state developed by Boggio-Pasqua et al. [Mol. Phys. 98, 1925 （2000）]. The product angular distributions which reflect the vector correlation have been calculated. In addition, two polarization-dependent different cross-sections are also presented in the center-of-mass frame respectively. The results indicate that the product C2 is sensitively affected by collision energy.
基金Supported by the National Natural Science Foundation of China(No10604012)
文摘The Ca＋CH3I→CaI＋CH3 reaction system has been studied with the quasi-classical trajectory method on the extended Lond-Eyring-Polanyi-Sato（LEPS） potential energy surface. At collision energy Ecol=10.78 kJ/mol, the calculated results show that the CaI vibrational population peaks are located at v=2. The calculated cross section decreases slowly with the collision energy increasing. The angle product distributions tend toward backward scattering. The calculated （P2（J^1·K）） values deviate slightly from-0.5 and decrease with increasing collision energy. The Quasiclassical trajectory calculation（QCT） results are in reasonable agreement with experimental data. Moreover, the dynamics of the reaction has been discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.11004107)the Scientific Research Innovation Projects of Jiangsu Province for University Graduate Students,China(Grant No.CXZZ13 0201)
文摘The isotope effect on the stereodynamic properties in the title reaction is investigated by a quasi-classical trajectory （QCT） method on the 11At potential energy surface at a collision energy of 23.06 kcal/mol. The angular distributions P（φr ）, P（θr）, P（θr, φr）, and the polarization-dependent generalized differential cross sections are calculated, which demonstrate the observable influences on the rotational polarization of the product by the isotopic substitution of H with D.
文摘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.
基金Project supported by the National Natural Science Foundation of China (Grant No.21073110)the Independent Innovation Foundation of Shandong University of China (Grant No.10000059614011)
文摘We have carried out a quasi-classical trajectory calculation for the reaction ofNe ＋ H2＋ （v = 0, j = 1） → NeH＋ ＋ H on the ground state （12AI） using the LZHH potential energy surface constructed by L/i et al. [Lu S J, Zhang P Y, Han K L and He G Z 2010 J. Chem. Phys. 132 014303]. Differential cross sections at many collision energies indicate that the reaction is dominated by forward-scattering. In addition, the Nell＋ product shows rotationally hot and vibrationally cold distributions. Stereodynamical results indicate that the products are strongly polarized in the direction perpendicular to the scattering plane and that the products rotate mainly in planes parallel to the scattering plane.
基金co-supported by the National Natural Science Foundation of China(No.12072365)the Technology Innovation Team of Manned Space Engineering,China。
文摘Aimed at the demand of contingency return at any time during the near-moon phase in the manned lunar landing missions,a fast calculation method for three-impulse contingency return trajectories is proposed.Firstly,a three-impulse contingency return trajectory scheme is presented by combining the Lambert transfer and maneuver at the special point.Secondly,a calculation model of three-impulse contingency return trajectories is established.Then,fast calculation methods are proposed by adopting the high-order Taylor expansion of differential algebra in the twobody trajectory dynamics model and perturbed trajectory dynamics model.Finally,the performance of the proposed methods is verified by numerical simulation.The results indicate that the fast calculation method of two-body trajectory has higher calculation efficiency compared to the semi-analytical calculation method under a certain accuracy condition.Due to its high efficiency,the characteristics of the three-impulse contingency return trajectories under different contingency scenarios are further analyzed expeditiously.These findings can be used for the design of contingency return trajectories in future manned lunar landing missions.
文摘Quasi-classical trajectory(QCT)calculations are reported for the H+LiH(v=0-2,j=0)→Li+H2 reaction on a new ground electronic state global potential energy surface(PES)of the LiH2 system.Reaction probability and integral cross sections(ICSs)are calculated for collision energies in the range of 0 eV-0.5 eV.Reasonable agreement is found in the comparison between present results and previous available theoretical results.We carried out statistical analyses with all the trajectories and found two main distinct reaction mechanisms in the collision process,in which the stripping mechanism(i.e.,without roaming process)is dominated over the collision energy range.The polarization dependent differential cross sections(PDDCSs)indicate that forward scattering dominates the reaction due to the dominated mechanism.Furthermore,the reactant vibration leads to a reduction of the reactivity because of the barrierless and attractive features of PES and mass combination of the system.
基金supported by the National Natural Science Foundation of China(Grant Nos.10874096 and 20633070)the Natural Science Foundation of Qingdao University,China(Grant No.063-06300510)
文摘The stereodynamic properties of the F+HO(v,j)reaction are explored by quasi-classical trajectory(QCT)calculations performed on the 1At and 3At potential energy surfaces(PESs).Based on the polarization-dependent differential cross sections(PDDCSs)and the angular distributions of the product angular momentum with the reactant at different values of initial v or j,the results show that the product scattering and product polarization have strong links with initial vibrationalrotational numbers of v and j.The significant manifestation of the normal DCSs is that the forward scattering gradually becomes predominant with the initial vibrational excitation increasing,and the scattering angle of the HF product taking place on the 3At potential energy surface is found to be more sensitive to the initial value of v.The product orientation and alignment are strongly dependent on the initial rovibrational excitation effect.With enhancement in the initial rovibrational excitation effect,there is an overall decrease in the product orientation as well as in the product alignment either perpendicular to the reagent relative velocity vector k or along the direction of the y axis,for which the initial rotational excitation effect is much more noticeable than the vibrational excitation effect.Moreover,the initial rovibrational excitation effect on the product polarization is more pronounced for the 3At potential energy surface than for the 1At potential energy surface.
基金supported by the National Natural Science Foundation of China (Grant No. 11074151)the National Basic Research Program of China (Grant No. 2011CB808105)the Open Fund of the State Key Laboratory of High Field Laser Physics(Shanghai Institute of Optics and Fine Mechanics)
文摘The vector properties of reaction O（1D）＋HBr→OH＋Br on the potential energy surface （PES） of X1A＇ ground singlet state are studied by using the quasi-classical trajectory （QCT） theory. The polarization-dependent differential cross sections （PDDCSs）, the average rotational alignment factor （P 2 （j＇- k）〉, as well as the distributions reflecting vector correlations are also computed. The analysis of the results shows that the alignment and the orientation distribution of the rotation angular momentum vector of product molecule OH is influenced by both the effect of heavy-light heavy （HLH） type mass combination and the deep well of PES.
基金Project supported by the Science Fund from Jilin University,China(Grant No.419080106440)the Chinese National Fusion Project for ITER(Grant No.2010GB104003)the National Natural Science Foundation of China(Grant No.10974069)
文摘Quasi-classical trajectory （QCT） studies on the stereodynamics of H ＋ BrO → O＋ HBr reaction have been performed on the X1A＇ state of ab initio potential energy surface by Peterson [Peterson K A 2000 J. Chem. Phys. 113 4598] in a collision energy range from 0 kcal/mol to 6 kcal/mol. Two of the polarization-dependent generalized differential cross sections （PDDCSs）, （2π/σ）（dσ 00/d ω） （PDDCSoo） and （2π/σ）（dσ20/doh） （PDDCS20） are considered. The rotational polarizations of these products show sensitive behaviors to the calculated collision energy range. Furthermore, in order to gain more knowledge about vector correlations, the product angular distribution, P（θr）, and the dihedral angle, P （Фr）, are calculated, and the results indicate that both the rotational alignment and orientation of the product are enhanced as collision energy increases.
基金supported by the National Natural Science Foundation of China(No.21973009)Chongqing Municipal Natural Science Foundation(No.cstc2019jcyj-msxm X0087)。
文摘The reaction H+SO_(2)→OH+SO is important in the combustion and atmospheric chemistry,as well as the interstellar medium.It also represents a typical complex-forming reaction with deep complexes,serving as an ideal candidate for testing various kinetics theories and providing interesting reaction dynamical phenomena.In this work,we reported a quasiclassical trajectory study of this reaction on our previously developed accurate full-dimensional potential energy surface.The experimental thermal rate coefficients over the temperature range 1400 K≤T≤2200 K were well reproduced.For the reactant SO_(2)being sampled at the ground ro-vibrational state,the calculated integral cross sections increased slightly along the collision energy ranging from 31.0 kcal/mol to 40.0 kcal/mol,and then became essentially flat at the collision energy within 40.0−55.0 kcal/mol.The product angular distributions are almost symmetric with nearly identical backward-forward double peak structure.The products OH and SO vibrational state distributions were also analyzed.
基金supported by the National Natural Science Foundation of China(No.22073073)the Startup Foundation of Northwest UniversityThe Double First-Class University Construction Project of Northwest University。
文摘A quasi-classical trajectory study of the H(^(2)S)+NO(X^(2)Π)→N(^(4)S)+OH(X^(2)Π) reaction kinetics and dynamics is reported on an accurate potential energy surface.The total integral cross sections of the reaction were calculated at the collision energy ranging from 2.00 e V to 2.80 e V.It was found that the total reaction integral cross section increases monotonically with the collision energy.Specifically at the collision energy range of 2.40-2.57 e V,our calculated results are in reasonably good agreement with the experimental data.The calculated thermal rate constants are in fairly good agreement with available experimental results.Through the trajectory analysis at the collision energy of 2.57 e V,it was found that the title reaction is dominated by the indirect trajectories(1.4 times more compared to the direct trajectories),which sheds light on the reaction dynamics of the title reaction in the high collision energy range.
基金Project supported by the Fund from the Jilin University,China(Grant No.419080106440)the Chinese National Fusion Project for the International Thermonuclear Experimental Reactor(ITER)(Grant No.2010GB104003)the National Natural Science Foundation of China(Grant No.10974069)
文摘In this paper, the stereodynamics of Li ＋ DF → Li F ＋ D reaction is investigated by the quasi-classical trajectory（QCT）method on the ^2A＇ potential energy surface（PES） at a relatively low collision energy of 8.76 kcal/mol. The scalar properties of the title reaction such as reaction probability and cross section are studied with vibrational quantum number of v = 1–6. The product angular distributions P（θr） and P（φr） are presented in the same vibrational level range. Moreover, two polarization-dependent generalized differential cross sections（PDDCSs）, i.e., the PDDCS00 and PDDCS22＋are calculated as well. These stereodynamical results demonstrate sensitive behaviors to the vibrational quantum numbers.
文摘The principle of direct method used in optimal control problem is introduced. Details of applying this method to flight trajectory generation are presented including calculation of velocity and controls histories. And capabilities of flight and propulsion systems are considered also. Combined with digital terrain map technique, the direct method is applied to the three dimensional trajectory optimization for low altitude penetration, and simplex algorithm is used to solve the parameters in optimization. For the small number of parameters, the trajectory can be optimized in real time on board.
基金supported by the National Natural Science Foundation of China (No.61203022)the Aeronautical Science Foundation of China (2012CZ51029)
文摘In view of generating optimal trajectories of Bolza problems, standard Chebyshev pseudospectral （PS） method makes the points＇ accumulation near the extremities and rarefaction of nodes close to the center of interval, which causes an ill-condition of differentiation matrix and an oscillation of the optimal solution. For improvement upon the difficulties, a mapped Chebyshev pseudospectral method is proposed. A conformal map is applied to Chebyshev points to move the points closer to equidistant nodes. Condition number and spectral radius of differentiation matrices from both methods are presented to show the improvement. Furthermore, the modification keeps the Chebyshev pseudospectral method＇s advantage, the spectral convergence rate. Based on three numerical examples, a comparison of the execution time, convergence and accuracy is presented among the standard Chebyshev pseudospectral method, other collocation methods and the proposed one. In one example, the error of results from mapped Chebyshev pseudospectral method is reduced to 5% of that from standard Chebyshev pseudospectral method.
文摘Aiming at increasing the calculation efficiency of the pseudospectral methods, a multiple- interval Radau pseudospectral method （RPM） is presented to generate a reusable launch vehicle （RLV） ＇s optimal re-entry trajectory. After dividing the optimal control problem into many intervals, the state and control variables are approximated using many fixed- and low-degree Lagrange polyno- mials in each interval. Convergence of the numerical discretization is then achieved by increasing the number of intervals. With the application of the proposed method, the normal nonlinear program- ming （NLP） problem transcribed from the optimal control problem can avoid being dense because of the low-degree approximation polynomials in each interval. Thus, the NLP solver can easily compute a solution. Finally, simulation results show that the optimized re-entry trajectories satisfy the path constraints and the boundary constraints successfully. Compared with the single interval RPM, the multiple-interval RPM is significantly faster and has higher calculation efficiency. The results indicate that the multiple-interval RPM can be applied for real-time trajectory generation due to its high effi- ciency and high precision.
