We propose a method for calculating the nonradiative decay rates for polyatomic molecules including anharmonic effects of the potential energy surface(PES)in the Franck-Condon region.The method combines the n-mode rep...We propose a method for calculating the nonradiative decay rates for polyatomic molecules including anharmonic effects of the potential energy surface(PES)in the Franck-Condon region.The method combines the n-mode repre-sentation method to construct the ab initio PES and the nearly exact time-dependent density matrix renormalization group method(TD-DMRG)to simulate quantum dynamics.In addition,in the framework of TD-DMRG,we further develop an algorithm to calculate the final-state-resolved rate coefficient which is very useful to analyze the contribution from each vibrational mode to the transition process.We use this method to study the internal conversion(IC)process of azulene after taking into account the anharmonicity of the ground state PES.The results show that even for this semi-rigid molecule,the intramode anharmonicity enhances the IC rate significantly,and after considering the two-mode coupling effect,the rate increases even further.The reason is that the anharmonicity enables the C-H vibrations to receive electronic energy while C-H vibrations do not contribute on the harmonic PES as the Huang-Rhys factor is close to 0.展开更多
Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batter...Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batteries more competitive,combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance.In this study,we prepare a type of multifunctional V3S4-nanowire/graphene composites(V3S4-G)by uniformly dispersing V3S4 nanowires on the graphene substrate.This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics.Thus,the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability.Even at sulfur loading of 3 mg cm^−2,the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186%per cycle at 0.5 C.展开更多
基金supported by the National Natural Science Foundation of China through the Project "Science Center for Luminescence from Molecular Aggregates(SCELMA)" (No.21788102)the Ministry of Science and Technology of China through the National Key R&D Plan (No.2017YFA0204501)supported by the National Natural Science Foundation of China (No.22003029)
文摘We propose a method for calculating the nonradiative decay rates for polyatomic molecules including anharmonic effects of the potential energy surface(PES)in the Franck-Condon region.The method combines the n-mode repre-sentation method to construct the ab initio PES and the nearly exact time-dependent density matrix renormalization group method(TD-DMRG)to simulate quantum dynamics.In addition,in the framework of TD-DMRG,we further develop an algorithm to calculate the final-state-resolved rate coefficient which is very useful to analyze the contribution from each vibrational mode to the transition process.We use this method to study the internal conversion(IC)process of azulene after taking into account the anharmonicity of the ground state PES.The results show that even for this semi-rigid molecule,the intramode anharmonicity enhances the IC rate significantly,and after considering the two-mode coupling effect,the rate increases even further.The reason is that the anharmonicity enables the C-H vibrations to receive electronic energy while C-H vibrations do not contribute on the harmonic PES as the Huang-Rhys factor is close to 0.
基金We acknowledge the financial support from the National Key R&D Program of China(2016YFA0200102 and 2017YFA0206301)the National Natural Science Foundation of China(51631001,51590882,51672010 and 81421004).
文摘Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batteries more competitive,combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance.In this study,we prepare a type of multifunctional V3S4-nanowire/graphene composites(V3S4-G)by uniformly dispersing V3S4 nanowires on the graphene substrate.This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics.Thus,the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability.Even at sulfur loading of 3 mg cm^−2,the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186%per cycle at 0.5 C.
