An accurate theoretical study on the MgH radical is reported by adopting the high-level relativistic MRCI＋Q method with a quintuple-zeta quality basis set. The reliable potential energy curves of the five A-S states ...An accurate theoretical study on the MgH radical is reported by adopting the high-level relativistic MRCI＋Q method with a quintuple-zeta quality basis set. The reliable potential energy curves of the five A-S states of MgH are derived. Then the associated spectroscopic parameters are determined and found to be in good accordance with the available experimental results. The permanent dipole moments （PDMs） and the spin-orbit （SO） matrix elements of A-S states are computed. The results show that the abrupt changes of PDMs and SO matrix elements are attributed to the variations of electronic configurations at the avoided crossing point. The SOC effect leads to the five A-S states split into ten Ω states and results in the double potential well of （2）1//2 state. Finally, the transition properties from the （2）1//2, （1）3//2 and （3）1//2 states to the ground state X2∑＋1//2 transitions are obtained, including the transition dipole moments, Franck-Condon factors and radiative lifetimes.展开更多
Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers.Therefore,parallel tempering Monte Carlo simulation was used in order to get fast thermalisation(to minimiz...Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers.Therefore,parallel tempering Monte Carlo simulation was used in order to get fast thermalisation(to minimize the relaxation time).Distance dependent interaction coupling in 2D is studied in order to show how a spin glass phase transition occurs when couplings between far away spins are permitted by considering Edwards-Anderson Ising spin glass model.The interaction coupling is a quenched random variable whose probability of being non-zero decays with distance between two spin sites rij=|i-j|mod(L/2).The interaction coupling is random and its probability distribution is decaying with the distance between the spins(p(Jij)αrij^-ρ).The model is studied by changing p among three different regimes(p〉2D,4/3 D〈p〈2D,p〈4/3D).A phase transition temperature for p=2,3,4 is obtained.展开更多
Two-dimensional transition metal dichalcogenides（TMDs） have attracted extensive attention due to their many novel properties.The atoms within each layer in two-dimensional TMDs are joined together by covalent bonds,...Two-dimensional transition metal dichalcogenides（TMDs） have attracted extensive attention due to their many novel properties.The atoms within each layer in two-dimensional TMDs are joined together by covalent bonds,while van der Waals interactions combine the layers together.This makes its lattice dynamics layer-number dependent.The evolutions of ultralow frequency（〈 50 cm^（-1）） modes,such as shear and layer-breathing modes have been well-established.Here,we review the layer-number dependent high-frequency（〉 50 cm^（-1）） vibration modes in few-layer TMDs and demonstrate how the interlayer coupling leads to the splitting of high-frequency vibration modes,known as Davydov splitting.Such Davydov splitting can be well described by a van der Waals model,which directly links the splitting with the interlayer coupling.Our review expands the understanding on the effect of interlayer coupling on the high-frequency vibration modes in TMDs and other two-dimensional materials.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11564019,11574114,11147158,91221301 and 11264020the Natural Science Foundation of Jilin Province under Grant No 20150101003JC
文摘An accurate theoretical study on the MgH radical is reported by adopting the high-level relativistic MRCI＋Q method with a quintuple-zeta quality basis set. The reliable potential energy curves of the five A-S states of MgH are derived. Then the associated spectroscopic parameters are determined and found to be in good accordance with the available experimental results. The permanent dipole moments （PDMs） and the spin-orbit （SO） matrix elements of A-S states are computed. The results show that the abrupt changes of PDMs and SO matrix elements are attributed to the variations of electronic configurations at the avoided crossing point. The SOC effect leads to the five A-S states split into ten Ω states and results in the double potential well of （2）1//2 state. Finally, the transition properties from the （2）1//2, （1）3//2 and （3）1//2 states to the ground state X2∑＋1//2 transitions are obtained, including the transition dipole moments, Franck-Condon factors and radiative lifetimes.
文摘Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers.Therefore,parallel tempering Monte Carlo simulation was used in order to get fast thermalisation(to minimize the relaxation time).Distance dependent interaction coupling in 2D is studied in order to show how a spin glass phase transition occurs when couplings between far away spins are permitted by considering Edwards-Anderson Ising spin glass model.The interaction coupling is a quenched random variable whose probability of being non-zero decays with distance between two spin sites rij=|i-j|mod(L/2).The interaction coupling is random and its probability distribution is decaying with the distance between the spins(p(Jij)αrij^-ρ).The model is studied by changing p among three different regimes(p〉2D,4/3 D〈p〈2D,p〈4/3D).A phase transition temperature for p=2,3,4 is obtained.
基金Project supported by the National Basic Research Program of China(No.2016YFA0301200)the National Natural Science Foundation of China(Nos.11225421,11474277,11434010,61474067,11604326,11574305 and 51527901)the National Young 1000 Talent Plan of China
文摘Two-dimensional transition metal dichalcogenides（TMDs） have attracted extensive attention due to their many novel properties.The atoms within each layer in two-dimensional TMDs are joined together by covalent bonds,while van der Waals interactions combine the layers together.This makes its lattice dynamics layer-number dependent.The evolutions of ultralow frequency（〈 50 cm^（-1）） modes,such as shear and layer-breathing modes have been well-established.Here,we review the layer-number dependent high-frequency（〉 50 cm^（-1）） vibration modes in few-layer TMDs and demonstrate how the interlayer coupling leads to the splitting of high-frequency vibration modes,known as Davydov splitting.Such Davydov splitting can be well described by a van der Waals model,which directly links the splitting with the interlayer coupling.Our review expands the understanding on the effect of interlayer coupling on the high-frequency vibration modes in TMDs and other two-dimensional materials.
