A wide range of quantum systems are time-invariant and the corresponding dynamics is dic- tated by linear differential equations with constant coefficients. Although simple in math- ematical concept, the integration o...A wide range of quantum systems are time-invariant and the corresponding dynamics is dic- tated by linear differential equations with constant coefficients. Although simple in math- ematical concept, the integration of these equations is usually complicated in practice for complex systems, where both the computational time and the memory storage become limit- ing factors. For this reason, low-storage Runge-Kutta methods become increasingly popular for the time integration. This work suggests a series of s-stage sth-order explicit Runge- Kutta methods specific for autonomous linear equations, which only requires two times of the memory storage for the state vector. We also introduce a 13-stage eighth-order scheme for autonomous linear equations, which has optimized stability region and is reduced to a fifth-order method for general equations. These methods exhibit significant performance improvements over the previous general-purpose low-stage schemes. As an example, we ap- ply the integrator to simulate the non-Markovian exciton dynamics in a 15-site linear chain consisting of perylene-bisimide derivatives.展开更多
Recent experiments report the rotation of FA(FA=HC[NH2]2+)cations significantly influence the excited-state lifetime of FAPbI3.However,the underlying mechanism remains unclear.Using ab initio nonadiabatic(NA)molecular...Recent experiments report the rotation of FA(FA=HC[NH2]2+)cations significantly influence the excited-state lifetime of FAPbI3.However,the underlying mechanism remains unclear.Using ab initio nonadiabatic(NA)molecular dynamics combined with time-domain density functional simulations,we have demonstrated that reorientation of partial FA cations significantly inhibits nonradiative electron-hole recombination with respect to the pristine FAPbI3 due to the decreased NA coupling by localizing electron and hole in different positions and the suppressed atomic motions.Slow nuclear motions simultaneously increase the decoherence time,which is overcome by the reduced NA coupling,extending electron-hole recombination time scales to several nanoseconds and being about 3.9 times longer than that in pristine FAPbI3,which occurs within sub-nanosecond and agrees with experiment.Our study established the mechanism for the experimentally reported prolonged excited-state lifetime,providing a rational strategy for design of high performance of perovskite solar cells and optoelectronic devices.展开更多
The photodissociation of Br2 was investigated within the near-visible UV absorption band. Based on the potential curves for the ground and low-lying excited states, the optical cross-sections for the discrete transiti...The photodissociation of Br2 was investigated within the near-visible UV absorption band. Based on the potential curves for the ground and low-lying excited states, the optical cross-sections for the discrete transitions of C1^Пu,B^3Пou^＋, A^3П1u←X^1∑g＋ and their total energy absorption spectrum are derived, and the quantum yield of （Br＋Br6＊） channel are determined correspondingly. The one-dimensional Landau-Zener model is used to evaluate the behavior of curve crossing during photodissociation. The results indicate that the influence of nonadiabatic mechanism, which may be caused by the electronic-vibrational interplay between the 13 and C states, is negligibly small for the （Br＋Br^＊） channel. From the Landau-Zener modeling of the observed product recoil parameter β（Br＋Br）, the best-fit value of the coupling matrix elenment or coupling strength between the diabatic B and C state potentials is obtained.展开更多
Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthes...Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthesized paddle-wheel BODIPY-hexaoxatriphenylene(BODIPY is the abbreviation for BF_(2)-chelated dipyrromethenes)conjugates D-A complexes with the combination of both electronic structure calculations and nonadiabatic dynamics simulations.On the basis of computational results,we concluded that the BODIPY-hexaoxatriphenylene(BH)conjugates will be promoted to the local excited(LE)states of the BODIPY fragments upon excitation,which is followed by the ultrafast exciton transfer from LE state to charge transfer(CT).Instead of the photoinduced electron transfer process proposed in previous experimental work,such a exciton transfer process is accompanied with the photoinduced hole transfer from BODIPY to hexaoxatriphenylene.Additionally,solvent effects are found to play an important role in the photoinduced dynamics.Specifically,the hole transfer dynamics is accelerated by the acetonitrile solvent,which can be ascribed to significant influences of the solvents on the charge transfer states,i.e.the energy gaps between LE and CT excitons are reduced greatly and the non-adiabatic couplings are increased in the meantime.Our present work not only provides valuable insights into the underlying photoinduced mechanism of BH,but also can be helpful for the future design of novel donor-acceptor conjugates with better optoelectronic performance.展开更多
基金This work is supported by the National Natural Science Foundation of China （No.21373064）, the Program for Innovative Research Team of Guizhou Province （No.QKTD[2014]4021）, and the Natural Sci- entific Foundation from Guizhou Provincial Department of Education （No.ZDXK[2014]IS）. All the calculations were performed at Guizhou Provincial High- Performance Computing Center of Condensed Mate- rials and Molecular Simulation in Guizhou Education University.
文摘A wide range of quantum systems are time-invariant and the corresponding dynamics is dic- tated by linear differential equations with constant coefficients. Although simple in math- ematical concept, the integration of these equations is usually complicated in practice for complex systems, where both the computational time and the memory storage become limit- ing factors. For this reason, low-storage Runge-Kutta methods become increasingly popular for the time integration. This work suggests a series of s-stage sth-order explicit Runge- Kutta methods specific for autonomous linear equations, which only requires two times of the memory storage for the state vector. We also introduce a 13-stage eighth-order scheme for autonomous linear equations, which has optimized stability region and is reduced to a fifth-order method for general equations. These methods exhibit significant performance improvements over the previous general-purpose low-stage schemes. As an example, we ap- ply the integrator to simulate the non-Markovian exciton dynamics in a 15-site linear chain consisting of perylene-bisimide derivatives.
基金supported by the National Natural Science Foundation of China(No.21573022 and No.51861135101)the Recruitment Program of Global Youth Experts of Chinathe Beijing Normal University Startup。
文摘Recent experiments report the rotation of FA(FA=HC[NH2]2+)cations significantly influence the excited-state lifetime of FAPbI3.However,the underlying mechanism remains unclear.Using ab initio nonadiabatic(NA)molecular dynamics combined with time-domain density functional simulations,we have demonstrated that reorientation of partial FA cations significantly inhibits nonradiative electron-hole recombination with respect to the pristine FAPbI3 due to the decreased NA coupling by localizing electron and hole in different positions and the suppressed atomic motions.Slow nuclear motions simultaneously increase the decoherence time,which is overcome by the reduced NA coupling,extending electron-hole recombination time scales to several nanoseconds and being about 3.9 times longer than that in pristine FAPbI3,which occurs within sub-nanosecond and agrees with experiment.Our study established the mechanism for the experimentally reported prolonged excited-state lifetime,providing a rational strategy for design of high performance of perovskite solar cells and optoelectronic devices.
基金ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China （No.10534010 and No.20673140）.
文摘The photodissociation of Br2 was investigated within the near-visible UV absorption band. Based on the potential curves for the ground and low-lying excited states, the optical cross-sections for the discrete transitions of C1^Пu,B^3Пou^＋, A^3П1u←X^1∑g＋ and their total energy absorption spectrum are derived, and the quantum yield of （Br＋Br6＊） channel are determined correspondingly. The one-dimensional Landau-Zener model is used to evaluate the behavior of curve crossing during photodissociation. The results indicate that the influence of nonadiabatic mechanism, which may be caused by the electronic-vibrational interplay between the 13 and C states, is negligibly small for the （Br＋Br^＊） channel. From the Landau-Zener modeling of the observed product recoil parameter β（Br＋Br）, the best-fit value of the coupling matrix elenment or coupling strength between the diabatic B and C state potentials is obtained.
基金supported by the National Natural Science Foundation of China(No.22003043 for Xiang-Yang Liu)the National Natural Science Foundation of China(No.21688102,No.21590801,and No.21520102005 for Ganglong Cui)+1 种基金Sichuan Science and Technology Program(No.2020YJ0161 for Xiang-Yang Liu)the High Performance Computing Center of Sichuan Normal University。
文摘Understanding the excited state dynamics of donor-acceptor(D-A)complexes is of fundamental importance both experimentally and theoretically.Herein,we have first explored the photoinduced dynamics of a recently synthesized paddle-wheel BODIPY-hexaoxatriphenylene(BODIPY is the abbreviation for BF_(2)-chelated dipyrromethenes)conjugates D-A complexes with the combination of both electronic structure calculations and nonadiabatic dynamics simulations.On the basis of computational results,we concluded that the BODIPY-hexaoxatriphenylene(BH)conjugates will be promoted to the local excited(LE)states of the BODIPY fragments upon excitation,which is followed by the ultrafast exciton transfer from LE state to charge transfer(CT).Instead of the photoinduced electron transfer process proposed in previous experimental work,such a exciton transfer process is accompanied with the photoinduced hole transfer from BODIPY to hexaoxatriphenylene.Additionally,solvent effects are found to play an important role in the photoinduced dynamics.Specifically,the hole transfer dynamics is accelerated by the acetonitrile solvent,which can be ascribed to significant influences of the solvents on the charge transfer states,i.e.the energy gaps between LE and CT excitons are reduced greatly and the non-adiabatic couplings are increased in the meantime.Our present work not only provides valuable insights into the underlying photoinduced mechanism of BH,but also can be helpful for the future design of novel donor-acceptor conjugates with better optoelectronic performance.
