In order to theoretically study the growth morphology of dihydroxylammonium 5,5’-bistetrazole-1,1’-dio late(TKX-50)crystal in different solvent systems,crystal–solvent models were established,and then molecular dyn...In order to theoretically study the growth morphology of dihydroxylammonium 5,5’-bistetrazole-1,1’-dio late(TKX-50)crystal in different solvent systems,crystal–solvent models were established,and then molecular dynamics(MD)methods were adopted as a means to simulate particle motion.Modified attachment energy(MAE)model was employed to calculate the growth morphology of TKX-50.The simulation results demonstrate that COMPASS force field and RESP charge are suitable for molecular dynamics simulation of TKX-50.The morphologically dominant growth surfaces of TKX-50 in vacuum are(020),(011),(11–1),(100)and(120),respectively.In water(H_(2)O)and N,N-dimethylformamide(DMF)solvents,the(11–1)face is the largest in the habit face,the growth rate of(020)face becomes faster.With the increase of temperature,the aspect ratios of TKX-50 crystal in DMF solvent increase,and the areas of the(120)faces decrease.In ethylene glycol/H_(2)O mixed solvent system with volume ratio of 1/1,aspect ratio of TKX-50 is relatively small.In formic acid/H_(2)O mixed solvents with different volume ratios(1/4,1/3,1/2,1/1 and 2/1),aspect ratio of TKX-50 is relatively small when volume ratio is 1/2.展开更多
In this paper,the choice and parametrisation of finite deformation polyconvex isotropic hyperelastic models to describe the behaviour of a class of defect-free monocrystalline metal materials at the molecular level is...In this paper,the choice and parametrisation of finite deformation polyconvex isotropic hyperelastic models to describe the behaviour of a class of defect-free monocrystalline metal materials at the molecular level is examined.The article discusses some physical,mathematical and numerical demands which in our opinion should be fulfilled by elasticity models to be useful.A set of molecular numerical tests for aluminium and tungsten providing data for the fitting of a hyperelastic model was performed,and an algorithm for parametrisation is discussed.The proposed models with optimised parameters are superior to those used in non-linear mechanics of crystals.展开更多
In this paper, we report a method by which the ion quantity is estimated rapidly with an accuracy of 4%. This finding is based on the low-temperature ion density theory and combined with the ion crystal size obtained ...In this paper, we report a method by which the ion quantity is estimated rapidly with an accuracy of 4%. This finding is based on the low-temperature ion density theory and combined with the ion crystal size obtained from experiment with the precision of a micrometer. The method is objective, straightforward, and independent of the molecular dynamics （MD） simulation. The result can be used as the reference for the MD simulation, and the method can improve the reliability and precision of MD simulation. This method is very helpful for intensively studying ion crystal, such as phase transition, spatial configuration, temporal evolution, dynamic character, cooling efficiency, and the temperature limit of the ions.展开更多
A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and...A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and strong coupling limits, we can obtain very accurate GS energy for arbitrary electron-phonon coupling constant. Other GS properties are also discussed. Moreover, the present concise approach is hopefully generalized to many other Holstein models.展开更多
Crystal structure of conjugated molecules and polymers is fundamentally critical to understand their multilevel microstructures,carrier transport,and diverse functions.However,to determine the crystal structure of con...Crystal structure of conjugated molecules and polymers is fundamentally critical to understand their multilevel microstructures,carrier transport,and diverse functions.However,to determine the crystal structure of conjugated polymers is a significant challenge,mainly due to the poor crystallinity,weak diffraction,and instability under high-energy radiation.Here,we build the possible crystal structures of eight typical conjugated polymers,covering several widely used molecular segments in organic optoelectronics.We model the packing structures of these seed polymers based on synchrotron X-ray diffractions and molecular simulations.These crystal structures provide a new platform to predict the packing structures of more related polymer systems,extending the molecular scope.Based on this polymer crystal structure database,the multiscale microstructures and charge transport properties of conjugated polymers can be predicted before experiments.This study sets up a polymer crystal structure database to eliminate the current trial-and-error approaches and accelerating the design of high-performance conjugated polymers.展开更多
基金supported by Fundamental Research Program of Shanxi Province(20210302123055)and(201801D221035).
文摘In order to theoretically study the growth morphology of dihydroxylammonium 5,5’-bistetrazole-1,1’-dio late(TKX-50)crystal in different solvent systems,crystal–solvent models were established,and then molecular dynamics(MD)methods were adopted as a means to simulate particle motion.Modified attachment energy(MAE)model was employed to calculate the growth morphology of TKX-50.The simulation results demonstrate that COMPASS force field and RESP charge are suitable for molecular dynamics simulation of TKX-50.The morphologically dominant growth surfaces of TKX-50 in vacuum are(020),(011),(11–1),(100)and(120),respectively.In water(H_(2)O)and N,N-dimethylformamide(DMF)solvents,the(11–1)face is the largest in the habit face,the growth rate of(020)face becomes faster.With the increase of temperature,the aspect ratios of TKX-50 crystal in DMF solvent increase,and the areas of the(120)faces decrease.In ethylene glycol/H_(2)O mixed solvent system with volume ratio of 1/1,aspect ratio of TKX-50 is relatively small.In formic acid/H_(2)O mixed solvents with different volume ratios(1/4,1/3,1/2,1/1 and 2/1),aspect ratio of TKX-50 is relatively small when volume ratio is 1/2.
文摘In this paper,the choice and parametrisation of finite deformation polyconvex isotropic hyperelastic models to describe the behaviour of a class of defect-free monocrystalline metal materials at the molecular level is examined.The article discusses some physical,mathematical and numerical demands which in our opinion should be fulfilled by elasticity models to be useful.A set of molecular numerical tests for aluminium and tungsten providing data for the fitting of a hyperelastic model was performed,and an algorithm for parametrisation is discussed.The proposed models with optimised parameters are superior to those used in non-linear mechanics of crystals.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB821301 and 2010CB832803)the National Natural Science Foundation of China(Grant Nos.11004222 and 91121016)the Chinese Academy of Sciences
文摘In this paper, we report a method by which the ion quantity is estimated rapidly with an accuracy of 4%. This finding is based on the low-temperature ion density theory and combined with the ion crystal size obtained from experiment with the precision of a micrometer. The method is objective, straightforward, and independent of the molecular dynamics （MD） simulation. The result can be used as the reference for the MD simulation, and the method can improve the reliability and precision of MD simulation. This method is very helpful for intensively studying ion crystal, such as phase transition, spatial configuration, temporal evolution, dynamic character, cooling efficiency, and the temperature limit of the ions.
基金Supported by the National Natural Science Foundation of China under Grant Nos 19804009 and 10274067.
文摘A novel variational approach is proposed to calculate the ground-state （GS） properties of the two-site Holstein model. By the linear superposition of two coherent states, which simulate the behaviour of the weak and strong coupling limits, we can obtain very accurate GS energy for arbitrary electron-phonon coupling constant. Other GS properties are also discussed. Moreover, the present concise approach is hopefully generalized to many other Holstein models.
基金supported by National Key R&D Program of China(2017YFA0204701)National Natural Science Foundation of China(21420102005,21790360,21722201)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910001001).
文摘Crystal structure of conjugated molecules and polymers is fundamentally critical to understand their multilevel microstructures,carrier transport,and diverse functions.However,to determine the crystal structure of conjugated polymers is a significant challenge,mainly due to the poor crystallinity,weak diffraction,and instability under high-energy radiation.Here,we build the possible crystal structures of eight typical conjugated polymers,covering several widely used molecular segments in organic optoelectronics.We model the packing structures of these seed polymers based on synchrotron X-ray diffractions and molecular simulations.These crystal structures provide a new platform to predict the packing structures of more related polymer systems,extending the molecular scope.Based on this polymer crystal structure database,the multiscale microstructures and charge transport properties of conjugated polymers can be predicted before experiments.This study sets up a polymer crystal structure database to eliminate the current trial-and-error approaches and accelerating the design of high-performance conjugated polymers.
