The effect of collision energy on the stereodynamics of the reaction H(~2S)+NH(X^3∑^-,v = 0,j = 0)→ N(~4S)+H_2

The quasi-classical trajectory （QCT） is calculated to study the stereodynamics properties of the title reaction H（^2S） ＋ NH （X^3 ∑^-, v = 0, j = 0）→ N（^4S） ＋ H2 on the ground state ^4A″ potential energy surface （PES） constructed by Zhai and Han [2011 Jr. Chem. Phys. 135 104314]. The calculated QCT reaction probabilities and cross sections are in good agreement with the previous theoretical results. The effects of the collision energy on the k-kt distribution and the product polarization of H2 are studied in detail. It is found that the scattering direction of the product is strongly dependent on the collision energy. With the increase in the collision energy, the scattering directions of the products change from backward scattering to forward scattering. The distribution of P（Or） is strongly dependent on the collision energy below the lower collision energy （about 11.53 kcal/mol）. In addition, the P（（Pr） distribution dramatically changes as the collision energy increases. The calculated QCT results indicate that the collision energy plays an important role in determining the stereodynamics of the title reaction.

Crossed Beam Study on the F+D2→DF+D Reaction at Hyperthermal Collision Energy of 23.84 kJ/mol

We presented an experimental apparatus combining the H-atom Rydberg tagging time-of-flight technique and the laser detonation source for studying crossed beam reactions at hyperthermal collision energies. The preliminary study of the F+D2→DF+D reaction at hyperthermal collision energy of 23.84 kJ/mol was performed. Two beam sources were used in this study: one is the hyperthermal F beam source produced by a laser detonation process, and the other is D2 beam source generated by liquid-N2 cooled pulsed valve. Vibrational state-resolved di erential cross sections (DCSs) of product for the title reaction were determined. From the product vibrational state-resolved DCS, it can be concluded that products DF(v'=0, 1, 2, 3) are predominantly distributed in the sideway and backward scattering directions at this collision energy. However, the highest vibrational excited product DF(v'=4), is clearly peaked in the forward direction. The probable dynamical origins for these forward scattering products were analyzed and discussed.

The influence of collision energy on magnetically tuned^(6)Li-^(6)Li Feshbach resonance

The effect of collision energy on the magnetically tuned^(6)Li-^(6)Li Feshbach resonance(FR)is investigated theoretically by using the coupled-channel(CC)method for the collision energy ranging from 1μK·kBto 100μK·kB.At the collision energy of 1μK·kB,the resonance positions calculated are 543.152 Gs(s wave,the unit 1 Gs=10^(-4)T),185.109 Gs(p wave|ml|=0),and 185.113 Gs(p wave|ml|=1),respectively.The p-wave FR near 185 Gs exibits a doublet structure of 4 mGs,associated with dipole-dipole interaction.With the increase of the collision energy,it is found that the splitting width remains the same(4 mGs),and that the resonance positions of s and p waves are shifted to higher magnetic fields with the increase of collision energy.The variations of the other quantities including the resonance width and the amplitude of the total scattering section are also discussed in detail.The thermally averaged elastic rate coefficients at T=10,15,20,25 K are calculated and compared.

THEORETICAL INVESTIGATION OF COLLISION ENERGY EFFECT ON REACTION O(?) BARIUM WITH METHYL BROMIDE

The reac dynamics on Ba+BrCH_3→BaBr+CH_3 has been investigated in the first proposed potential energy surface of the generalized LEPS type,using the quasiclassical trajectory method.In simulation of the conditions in molecular beam experiments,the results of the present study show significant effect of the reagent collision energy on the dynamics of the reaction,and are in good agreement with the experimental ones.

The collision energy effect on the stereodynamics of the Ca + HCl→CaCl + H reaction

The stereodynamics of the reaction of Ca ＋ HCl are calculated at three different collision energies based on the potential energy surface [Verbockhaven G et al. 2005 J. Chem. Phys. 122 204307] using quasi-classical trajectory theory. The polarization-dependent differential cross sections （PDDCSs） （2π/σ ）（dσ 00 /dω t ）, （2π/σ ）（dσ 20 /dωt ）, （2π/σ ）（dσ 22＋ /dωt ）, （2π/σ ）（dσ 21 /dω t ） and the distributions of P（θ r ）, P（φr ）, and P（θr ,φr ） are calculated. The results indicate that the rotational polarization of the CaCl product presents different characteristics for the different collision energies, and the effects of the collision energy on the vector potential, including the alignment, orientation, and PDDCSs, are not obvious.

The study of intelligent algorithm in particle identification of heavy-ion collisions at low and intermediate energies

Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate energies.Researchers urgently need solutions to the dilemma of traditional particle identification methods.This study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate energies.Multiple intelligent algorithms,including XgBoost and TabNet,were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics(NIMROD-ISiS)and Geant4 simulation.Tree-based machine learning algorithms and deep learning algorithms e.g.TabNet show excellent performance and generalization ability.Adding additional data features besides energy deposition can improve the algorithm’s performance when the data distribution is nonuniform.Intelligent learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.

Laser-induced quadrupole-quadrupole collisional energy transfer in Xe-Kr

By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional energy transfer is presented. Calculated results in Xe-Kr system show that in the present system, the laser-induced collision process occurs for -4 ps, which is much shorter than the dipole-dipole laser-induced collisional energy transfer （LICET） process. The spectrum of laser-induced quadrupole quadrupole collisional energy transfer in Xe-Kr system has wider tunable range in an order of magnitude than the dipole-dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases.

Four-level model of ion-ion laser-induced collisional energy transfer and numerical calculations for Ca^+-Sr^+ system

The four-level model of laser-induced collisional energy transfer （LICET） for the ion-ion collision system is established based on the time-dependent SchrSdinger equation for the electron dynamics, through which the equations of motion of the probability amplitudes and cross section of the collision system are obtained. Numerical calculations are performed for the Ca＋ Sr＋ system, with the results showing that the peak of the LICET spectrum appears at a resonant frequency of the transfer laser. The magnitude of the obtained collision cross section is in the order of 10-16 cm2, and is comparable to that obtained in atomic systems, which indicates the validity of the established four-level model.

Stereodynamics Study of Li+HF→LiF+H Reactions on X^2A’ Potential Energy Surface at Collision Energies below 5.00 kcal/mol

The product rotational polarizations of reaction Li-SHF→LiF-kH at different collision energies, as well as at the different vibrational states and rotational states, are calculated by using the quasi-classical trajectory method based on a new potential energy surface constructed by Aguado et al. [J. Chem. Phys. 119（2003） 10088]. We investigate the Mignment and the orientation of the product molecule by calculating the P（θr, φr） distribu- tions describing polar angle distribution, the P（θr） distributions describing the k-j＇ correlation and the P（φr） distributions describing the k-k＇-j＇ correlation. We also explore the dependence of reaction probabilities and cross sections on the rotational and vibrational quantum number of the title reaction. It is concluded that the vibrational state has more important impact on the angular distribution, reaction probability and cross section.

Quasiclassical Trajectory Study of Collisional Energy Transfer between Highly Excited C_6F_6 and N_2 ,O_2 and Ground State C_6F_6

Quasiclassical trajectory calculation (QCT) is used frequently for studying collisional energy transfer between highly vibrationally excited molecules and bath gases. In this paper, the QCT of the energy transfer between highly vibrationally excited C6F6 and N2 ,O2 and ground state C6F6 were performed. The results indicate that highly vibrationally excited C6F6 transferred vibrational energy to vibrational distribution of N2, O2 and ground state C6F6, so they are V-V energy transfer. Especially it is mainly V-V resonance energy transfer between excited C6F6 and ground state C6F6, excited C6F6 transfers more vibrational energy to ground state C6F6 than to N2 and O2 . The values of QCT , -〈DEvib〉of excited C6F6 are smaller than those of experiments.

Laser-induced collisional energy transfer in Sr-Li system

A four-state model considering the relative velocity distribution function for calculating the cross section of laserinduced collisional energy transfer in a Sr Li system is presented and profiles of laser-induced collision cross section are obtained. The resulting spectra obtained from different intermediate states are strongly asymmetrical in an opposite asymmetry. Both of the two intermediate states have contributions to the final state, and none of the intermediate states should be neglected. The peak of the laser-induced collisional energy transfer （LICET） profile shifts toward the red and the FWHM becomes narrower obviously with laser field intensity increasing. A cross section of 1.2 × 10^-12 cm2 at a laser field intensity of 2.17 ×107 V/m is obtained, which indicates that this collision process can be an effective way to transfer energy selectively from a storage state to a target state. The existence of saturation for cross section with the increase of the laser intensity shows that the high-intensity redistribution of transition probabilities is an important feature of this process, which is not accounted for in a two-state treatment.

Electron excitation processes in low energy collisions of hydrogen-helium atoms

The electron excitation processes of H(1s)+He(1s^(2))→H(2s/2p)+He(1s^(2))are studied in impact energy range of 20-2000 e V/u by using the quantum-mechanical molecular orbital close-coupling(QMOCC)method.Total and state-selective cross sections have been obtained and compared with the available theoretical and experimental results.The results agree well with available measurements in the overlapping energy regions overall.The comparison of our results with other theoretical calculations further demonstrates the importance of considering a sufficient number of channels.The datasets presented in this paper,including the excitation cross sections,are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00083.

Charge transfer in low-energy collisions of Be^3+ and B^4+ ions with He

The nonradiative charge-transfer processes of Be3+(1s)/B4+(1s)colliding with He(1s2)are investigated by the quantum-mechanical molecular orbital close-coupling(QMOCC)method from 10 eV/u to 1800 eV/u.Total and state-selective cross sections are obtained and compared with other results available.Although the incident ions have the same number of electrons and collide with the same target,their cross sections are different due to the differences in molecular structure.For Be3+(1s)+He(1s2),only single-electron-capture(SEC)states are important and the total cross sections have a broad maximum around E=150 eV/u.While for B4+(1s)+He(1s2),both the SEC and double-electron-capture(DEC)processes are important,and the total SEC and DEC cross sections decrease rapidly with the energy decreasing.

Proton-Proton Collisions in View of Thermo-Statistical Approach

The data of charged particles produced in proton-proton collisions extracted from Durham particle data group at energy ranges √s = 6.3 - 17 GeV and at 0.9 - 7 TeV are investigated in the framework of Tsallis thermo-statistics and the Vlasov time dynamics. The analysis can describe the experimental data well all-over the considered energies and rapidity intervals. The variation of the collision parameters (chemical potential, entropy index and the time of evolution) is studied and discussed as a function of the final state temperature. According to the obtained result, a scenario, and a script of the time evolution for the particle production is simulated by the pp collision.

Differential Cross Sections of F+HD→DF+H Reaction at Collision Energies from 3.03 meV to 17.97 meV

The prototypical reaction of F+HD→DF+H was investigated at collision energies from 3.03 meV to 17.97 meV using a crossed molecular beam apparatus with multichannel Rydberg tagging time-of-flight detection.Significant contributions from both the BornOppenheimer(BO)forbidden reaction F^(*)(^(2)P_(1/2))+HD→DF+H and the BO-allowed reaction F(^(2)P_(3/2))+HD→DF+H were observed.In the backward scattering direction,the contribution from the BO-forbidden reaction F^(*)(^(2)P_(1/2))+HD was found to be considerably greater than the BO-allowed reaction F(^(2)P_(3/2))+HD,indicating the non-adiabatic effects play an important role in the dynamics of the title reaction at low collision energies.Collision-energy dependence of differential cross sections(DCSs)in the backward scattering direction was found to be monotonously decreased as the collision energy decreases,which does not support the existence of resonance states in this energy range.DCSs of both BO-allowed and BO-forbidden reactions were measured at seven collision energies from 3.03 meV to 17.97 meV.It is quite unexpected that the angular distribution gradually shifts from backward to sideway as the collision energy decreases from 17.97 meV to 3.03 meV,suggesting some unknown mechanisms may exist at low collision energies.

Analysis of structural behavior during collision event accounting for bow and side structure interaction

The main goal of this study was to investigate the effects of selected ship collision parameter values on the characteristics of the absorbed energy in several ship collision scenarios. Non-linear simulations were performed using a finite element method （FEM） to obtain virtual experiment data. In the present research, the size of the side damage from a collision phenomenon were measured and used to verify the numerical configuration together with the calculation results using an empirical equation. Parameters in the external dynamics of a ship collision such as the location of the contact point and velocity of the striking ship were taken into consideration. The internal energy and deformation size on the side structure were discussed further in a comparative study. The effects of the selected parameters on several structural behaviors, namely energy, force, and damage extent were also observed and evaluated in this section. Stiffener on side hull was found to contribute significantly into resistance capability of the target ship against penetration of the striking bow. Remarkable force during penetration was observed to occur when inner shell was crushed as certain velocity was applied in the striking bow.

Unified Hydrodynamics and Pseudorapidity Distributions of Charged Particles Produced in Heavy Ion Collisions at Low Energies at RHIC

In the context of unified hydrodynamics, we discuss the pseudorapidity distributions of the charged particles produced in Au-Au and Cu-Cu collisions at the low RHIC energies of √SNN = 19.6 and 22.4 GeV, respectively. It is found that the unified hydrodynamics alone can give a good description to the experimental measurements. This is different from the collisions at the maximum RHIC energy of √SNN = 200 GeV or at LHC energy of √SNN= 2.76 TeV, in which the leading particles must be taken into account so that we can properly explain the experimental observations.

Momentum-Dependent Symmetry Potential from Nuclear Collective Flows in Heavy Ion Collisions at Intermediate Energies

Within the isospin-dependent quantum molecular dynamics model, we investigate the nuclear collective flows produced in semi-central 197 Au＋197 Au collisions at intermediate energies. The neutron proton differential flows and difference of neutron proton collective flows are sensitive to the momentum-dependent symmetry potential. This sensitivity is less affected by both the isoscalar part of nuclear equation of state and in-medium nucleon- nucleon cross sections. Moreover, this sensitivity becomes pronounced with increasing the rapidity cut.

Experimental and Modeling Study of the Regular Polygon Angle-spiral Liner in Ball Mills

Load behavior is one of the most critical factors affecting mills＇ energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performances are extremely different. In order to study the performance of the ball mill with regular polygon angle-spiral liners（RPASLs）, experimental and numerical studies on three types of RPASLs, including regular quadrilateral, pentagonal and hexagonal, are carried out. For the fine product of desired size, two critical parameters are analyzed： the energy input to the mill per unit mass of the fine product, E＊, and the rate of production of the fine product, F＊. Results show that the optimal structure of RPASLs is Quadrilateral ASL with an assembled angle of 50°. Under this condition, the specific energy consumption E＊ has the minimum value of 303 J per fine product and the production rate F＊ has the maximum value of 0.323. The production rate F＊ in the experimental result is consistent with the specific collision energy intensity to total collision energy intensity ratio Es/Et in the simulation. The relations between the production rate F＊ and the specific energy consumption E＊ with collision energy intensity Es and Et are obtained. The simulation result reveals the essential reason for the experimental phenomenon and correlates the mill performance parameter to the collision energy between balls, which could guide the practical application for Quadrilateral ASL.

Appropriate choice of collision-induced dissociation energy for qualitative analysis of notoginsenosides based on liquid chromatography hybrid ion trap time-of-flight mass spectrometry

Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possesses both the MS^n ability of ion trap and the excellent resolution of a time-of-flight and has been widely used to identify drug metabolites and determine trace multi-components in natural products. Collision energy, one of the most important factors in acquiring MS^n information, could be set freely in the range of 10%–400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides were obtained based on accurate MS^2 and MS^3 measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. The extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract were produced under a series of collision energies and compared to screen the optimum collision energies values for MS^2 and MS^3. The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS^2 collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. Addtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS^3 stage.