In this paper,we theoretically investigate the effect of noise on the photoionization,the generation of the high-order harmonic and the attosecond pulse irradiated from a model He+ion.It shows that by properly adding ...In this paper,we theoretically investigate the effect of noise on the photoionization,the generation of the high-order harmonic and the attosecond pulse irradiated from a model He+ion.It shows that by properly adding noise fields,such as Gaussian white noise,random light or colored noise,both the ionization probabilities(IPs)and the harmonic yields can be enhanced by several orders of magnitude.Further,by tuning the noise intensity,a stochastic resonance-like curve is observed,showing the existence of an optimal noise in the ionization enhancement process.Finally,by superposing a properly selected harmonic,an intense attosecond pulse with a duration of 67 as is directly generated.展开更多
The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory....The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C ＂C bond-forming step with the addition of enamine intermediate to the imine for the L-proline（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-amino acid）-catalyzed processes were reported.B3LYP/6-31G calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts（syn-selectivity for the ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.展开更多
The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional....The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern.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
To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants,quasi-classical trajectory(QCT)calculation was performed on Ho's potential energy sur...To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants,quasi-classical trajectory(QCT)calculation was performed on Ho's potential energy surface(PES)of 2A″state.Product polarizations such as product distributions of P(θr),P(φr)and P(θr,φr),as well as the generalized polarization-dependent differential cross sections(PDDCSs)were discussed and compared in detail among the four product channels of the title reactions.Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.展开更多
The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet...The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet dynamics method.There is a quantitative agreement in all dominant features between the experiment and the theory.Moreover,a peak-splitting phenomenon in the first energy peak has been observed at high pulse intensity.Further,through the theoretical analysis,an ac Stark splitting with evident resonant and nonresonant ionization pathways has been found to be the physical reason for the experimental observations.展开更多
To investigate the isotopic effects and their influence on the stereodynamical properties of the N(^(4)S)+H_(2) reaction system,quasi−classical trajectory(QCT)calculations are carried out on the 4A"double many−bo...To investigate the isotopic effects and their influence on the stereodynamical properties of the N(^(4)S)+H_(2) reaction system,quasi−classical trajectory(QCT)calculations are carried out on the 4A"double many−body expansion(DMBE)potential energy surface(PES)[Phys.Chem.Chem.Phys.7(2005)2867]at a collision energy of 40 kcal/mol.The generalized polarization-dependent differential cross sections(PDDCSs)and the three angular distributions of P(θr),P(φr)and P(θr,φr)are presented and discussed for the title reaction and its isotope variants.It is revealed that both intermolecular and intramolecular isotope effects can exert a substantial influence on the product polarizations.展开更多
Flexible and lightweight Cu(In,Ga)Se2(CIGS)thin-film solar cells are promising for versatile applications,but there is limited understanding of stress-induced changes.In this study,the charge carrier generation and tr...Flexible and lightweight Cu(In,Ga)Se2(CIGS)thin-film solar cells are promising for versatile applications,but there is limited understanding of stress-induced changes.In this study,the charge carrier generation and trapping behavior undermechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments.Surface current at the CIGS surface decreased by convex bending,which occurs less with the incorporation of alkali metals.The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current.Moreover,alkali-related defects had lower formation energy than the intrinsic acceptors,mitigating current degradation in mechanical stress condition.The altered defect energy levels were attributed to the deformation of the crystal structure under bending states.This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices.展开更多
Droplet impact and breakup on meshes are relevant to a number of applications involving filters,textiles,and other spatially inhomogeneous media encountering gasdispersed liquids.This study presents high-resolution si...Droplet impact and breakup on meshes are relevant to a number of applications involving filters,textiles,and other spatially inhomogeneous media encountering gasdispersed liquids.This study presents high-resolution simulation results of mm-size droplets striking wettability-patterned meshes with the goal of(a)replicating prior physical experiments,(b)identifying sensitivities to the initial conditions and wettability of the mesh wires,and(c)studying the fluid-field dynamics when droplets strike such meshes.The insights from the present model may help to advance understanding of droplet atomization on meshes,which depends on a number of parameters that are nontrivial to control in an experimental setting.The analysis is carried out by benchmarking the numerical methods used in a commercial software package for orthogonal droplet impact on a flat smooth surface,followed by a convergence analysis,and finally,simulation of specific experiments and case studies involving wettability-patterned mesh targets.We show that the wettability contrast between the hydrophilic and hydrophobic domains on the mesh as well as the contact angle hysteresis on each side play a critical role in determining whether liquid pinchoff occurs.The three-dimensional computational framework constructed in this work is a step toward predicting the postimpact behavior of droplets that strike woven meshes and other porous inhomogeneous media consisting of materials with different wetting properties.展开更多
基金Project supported by the National Natural Science Foundations of China(Grant Nos.10874096 and 20633070)
文摘In this paper,we theoretically investigate the effect of noise on the photoionization,the generation of the high-order harmonic and the attosecond pulse irradiated from a model He+ion.It shows that by properly adding noise fields,such as Gaussian white noise,random light or colored noise,both the ionization probabilities(IPs)and the harmonic yields can be enhanced by several orders of magnitude.Further,by tuning the noise intensity,a stochastic resonance-like curve is observed,showing the existence of an optimal noise in the ionization enhancement process.Finally,by superposing a properly selected harmonic,an intense attosecond pulse with a duration of 67 as is directly generated.
基金Supported by the National Natural Science Foundation of China(Nos.20773071,20901043)the Natural Science Foundation of Shandong Province,China(No.ZR2010BM024)the Project of Shandong Province Higher Educational Science and Technology Program,China(No.J10LB06)
文摘The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C ＂C bond-forming step with the addition of enamine intermediate to the imine for the L-proline（·-amino acid） and （R）-3-pyrrolidinecarboxylic acid（·-amino acid）-catalyzed processes were reported.B3LYP/6-31G calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts（syn-selectivity for the ·-amino acid catalysts,anti-selectivity for the ·-amino acid catalysts）.Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.
文摘The excited-state double-proton transfer （ESDPT） mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory （DFT） and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern.
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(No.10874096)
文摘To figure out the influence of isotope effect on product polarizations of the N(2D)+D2 reactive system and its isotope variants,quasi-classical trajectory(QCT)calculation was performed on Ho's potential energy surface(PES)of 2A″state.Product polarizations such as product distributions of P(θr),P(φr)and P(θr,φr),as well as the generalized polarization-dependent differential cross sections(PDDCSs)were discussed and compared in detail among the four product channels of the title reactions.Both the intermolecular and intramolecular isotope effects were proved to be influential on product polarizations.
基金Project supported by the National Natural Science Foundations of China (Grant Nos. 10874096 and 20633070)
文摘The above-threshold ionization of argon in an intense 70-fs,400-nm linearly polarized laser pulse has been investigated by the velocity map imaging techniques,combined with an attosecond-resolution quantum wave packet dynamics method.There is a quantitative agreement in all dominant features between the experiment and the theory.Moreover,a peak-splitting phenomenon in the first energy peak has been observed at high pulse intensity.Further,through the theoretical analysis,an ac Stark splitting with evident resonant and nonresonant ionization pathways has been found to be the physical reason for the experimental observations.
基金by the National Natural Science Foundation of China under Grant No 10874096the Research Fund of Qingdao University under Grant Nos 063-06300510 and 20773071.
文摘To investigate the isotopic effects and their influence on the stereodynamical properties of the N(^(4)S)+H_(2) reaction system,quasi−classical trajectory(QCT)calculations are carried out on the 4A"double many−body expansion(DMBE)potential energy surface(PES)[Phys.Chem.Chem.Phys.7(2005)2867]at a collision energy of 40 kcal/mol.The generalized polarization-dependent differential cross sections(PDDCSs)and the three angular distributions of P(θr),P(φr)and P(θr,φr)are presented and discussed for the title reaction and its isotope variants.It is revealed that both intermolecular and intramolecular isotope effects can exert a substantial influence on the product polarizations.
基金supported by national R&D programs through the National Research Foundation of Korea(grant number:RS-2024-00355905,NRF-2018R1A6A1A03025340,NRF-2022M3J1A1064229)funded by the Ministry of Education and the Ministry of Science and ICT,and the framework of the Research and Development Program of the Korea Institute of Energy Research(grant number:C4-2412).
文摘Flexible and lightweight Cu(In,Ga)Se2(CIGS)thin-film solar cells are promising for versatile applications,but there is limited understanding of stress-induced changes.In this study,the charge carrier generation and trapping behavior undermechanical stress was investigated using flexible CIGS thin-film solar cells with various alkali treatments.Surface current at the CIGS surface decreased by convex bending,which occurs less with the incorporation of alkali metals.The formation energy of the carrier generating defects increased in convex bending environments clarifying the degradation of the surface current.Moreover,alkali-related defects had lower formation energy than the intrinsic acceptors,mitigating current degradation in mechanical stress condition.The altered defect energy levels were attributed to the deformation of the crystal structure under bending states.This study provides insights into the mitigating of strain-induced charge degradation for enhancing the performance and robustness of flexible CIGS photovoltaic devices.
文摘Droplet impact and breakup on meshes are relevant to a number of applications involving filters,textiles,and other spatially inhomogeneous media encountering gasdispersed liquids.This study presents high-resolution simulation results of mm-size droplets striking wettability-patterned meshes with the goal of(a)replicating prior physical experiments,(b)identifying sensitivities to the initial conditions and wettability of the mesh wires,and(c)studying the fluid-field dynamics when droplets strike such meshes.The insights from the present model may help to advance understanding of droplet atomization on meshes,which depends on a number of parameters that are nontrivial to control in an experimental setting.The analysis is carried out by benchmarking the numerical methods used in a commercial software package for orthogonal droplet impact on a flat smooth surface,followed by a convergence analysis,and finally,simulation of specific experiments and case studies involving wettability-patterned mesh targets.We show that the wettability contrast between the hydrophilic and hydrophobic domains on the mesh as well as the contact angle hysteresis on each side play a critical role in determining whether liquid pinchoff occurs.The three-dimensional computational framework constructed in this work is a step toward predicting the postimpact behavior of droplets that strike woven meshes and other porous inhomogeneous media consisting of materials with different wetting properties.
