Ericson formula represents the first formula, which was suggested to describe the partial level density (PLD) formula in pre-equilibrium region of the nuclear reactions. Then a number of corrections were added to this...Ericson formula represents the first formula, which was suggested to describe the partial level density (PLD) formula in pre-equilibrium region of the nuclear reactions. Then a number of corrections were added to this formula in order to make it more suitable to physical meaning. In this paper, there are two aims to be done: the first aim is to study the correspondence between one and two-components formulae in Ericson, Pauli, and pairing corrections;the second aim is to compare and study the results of Comprehensive formula, which contents with all corrections, with Ericson, Pauli, and pairing formulae. The Comprehensive formula was suggested to simulate the reality. To achieve these aims the 56Fe and 90Zr nuclei were chosen and the results showed that the difference between one and two-components formulae was too small which can be neglected. Furthermore, the results strongly recommended that for cross section calculations of the nuclear reaction, one must use Comprehensive formula rather than Pauli formula.展开更多
The two-componenl exciton model is applied for calculating the data ofnucleon induced reactions.The angular momentum and parity conservations are takeninto account.In terms of the calculated results of n+<sup>56...The two-componenl exciton model is applied for calculating the data ofnucleon induced reactions.The angular momentum and parity conservations are takeninto account.In terms of the calculated results of n+<sup>56</sup>Fe at E<sub>n</sub>=14.5 MeV the physicalpicture of the two-component model has been analysed.展开更多
To consider the angular momentum and parity conservation the angular mo-mentum (J) and parity (π) should be addressed in the master equation of the excitonmodel.Therefore the internal transition rates and the emissio...To consider the angular momentum and parity conservation the angular mo-mentum (J) and parity (π) should be addressed in the master equation of the excitonmodel.Therefore the internal transition rates and the emission rates must be Jπ depen-dent.The angular momentum factor of the internal transition rates is given and the an-gular momentum conservation effect is discussed.展开更多
The particle-hole state density in pre-equilibrium exciton model is required to calculate the cross section in pre-equilibrium nuclear reactions. In order to get a good match between theoretical and experimental data ...The particle-hole state density in pre-equilibrium exciton model is required to calculate the cross section in pre-equilibrium nuclear reactions. In order to get a good match between theoretical and experimental data the state density need to be corrected with some corrections. In this work some of the corrections that must be added to the state density have been collected all in an energy dependent correction functionJ~. The effects of adding Pauli Exclusion Principle, bound state, finite depth of the nuclear potential and pairing corrections have been examined to energies up to 100 MeV. The results were obtained using energy dependent single particle level density or the non equi-distant spacing model. Comparisons are made by adding some and full combination of the corrections to get an accurate and convenient choice in pre-equilibrium state density estimations. The results are compared with available experimental （Oslo）, and theoretical （HF-BCS） results. Results have been found matching the previously obtained experimental and theoretical results.展开更多
This paper studies the size dependence of biexciton binding energy in single quantum dots （QDs） by using atomic force microscopy and micro-photoluminescence measurements. It finds that the biexciton binding energies...This paper studies the size dependence of biexciton binding energy in single quantum dots （QDs） by using atomic force microscopy and micro-photoluminescence measurements. It finds that the biexciton binding energies in the QDs show ＂binding＂ and ＂antibinding＂ properties which correspond to the large and small sizes of QDs, respectively. The experimental results can be well interpreted by the biexciton potential curve, calculated from the exciton molecular model and the Heitler London method.展开更多
The exciton dispersion is examined in the case of four selected prototypical molecular solids: pentacene, tetracene, picene, and chrysene. The model parameters are determined by fitting to experimental data obtained b...The exciton dispersion is examined in the case of four selected prototypical molecular solids: pentacene, tetracene, picene, and chrysene. The model parameters are determined by fitting to experimental data obtained by inelastic electron scattering. Within the picture that relies on Frenkel-type excitons we obtain that theoretical dispersion curves along different directions in the Brillouin zone are in good agreement with the experimental data, suggesting that the influence of charge-transfer excitons on exciton dispersion of the analyzed organic solids is not as large as proposed. In reciprocal space directions where Davydov splitting is observed we employ the upgraded version of Hamiltonian used in Materials 11, 2219 (2018).展开更多
Based on the theoretical models for light nuclei, the calculations of reaction cross sections and the angular distributions for d ＋^8Li reaction are performed. Since all of the particle emissions are from the compoun...Based on the theoretical models for light nuclei, the calculations of reaction cross sections and the angular distributions for d ＋^8Li reaction are performed. Since all of the particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism is taken into account. The three- body break-up process and the recoil effect are involved. The theoretical calculated results are compared to existing experimental data.展开更多
We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same...We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.展开更多
采用单量子阱近似模型 ,对 In Ga N/ Ga N量子阱中的激子和电子在导带子带间跃迁的光吸收效应进行了理论分析和数值计算 .结果表明 ,In的含量对激子的能量影响较大 ,而量子阱宽度的变化也对激子的能量有着微调作用 ;导带中电子从基态至...采用单量子阱近似模型 ,对 In Ga N/ Ga N量子阱中的激子和电子在导带子带间跃迁的光吸收效应进行了理论分析和数值计算 .结果表明 ,In的含量对激子的能量影响较大 ,而量子阱宽度的变化也对激子的能量有着微调作用 ;导带中电子从基态至第一激发态跃迁的吸收峰比较明显 ;随着 In的含量增加 ,量子阱中的激子能量间隔增大 ,吸收谱线的峰值位置会发生蓝移 .展开更多
文摘Ericson formula represents the first formula, which was suggested to describe the partial level density (PLD) formula in pre-equilibrium region of the nuclear reactions. Then a number of corrections were added to this formula in order to make it more suitable to physical meaning. In this paper, there are two aims to be done: the first aim is to study the correspondence between one and two-components formulae in Ericson, Pauli, and pairing corrections;the second aim is to compare and study the results of Comprehensive formula, which contents with all corrections, with Ericson, Pauli, and pairing formulae. The Comprehensive formula was suggested to simulate the reality. To achieve these aims the 56Fe and 90Zr nuclei were chosen and the results showed that the difference between one and two-components formulae was too small which can be neglected. Furthermore, the results strongly recommended that for cross section calculations of the nuclear reaction, one must use Comprehensive formula rather than Pauli formula.
文摘The two-componenl exciton model is applied for calculating the data ofnucleon induced reactions.The angular momentum and parity conservations are takeninto account.In terms of the calculated results of n+<sup>56</sup>Fe at E<sub>n</sub>=14.5 MeV the physicalpicture of the two-component model has been analysed.
文摘To consider the angular momentum and parity conservation the angular mo-mentum (J) and parity (π) should be addressed in the master equation of the excitonmodel.Therefore the internal transition rates and the emission rates must be Jπ depen-dent.The angular momentum factor of the internal transition rates is given and the an-gular momentum conservation effect is discussed.
文摘The particle-hole state density in pre-equilibrium exciton model is required to calculate the cross section in pre-equilibrium nuclear reactions. In order to get a good match between theoretical and experimental data the state density need to be corrected with some corrections. In this work some of the corrections that must be added to the state density have been collected all in an energy dependent correction functionJ~. The effects of adding Pauli Exclusion Principle, bound state, finite depth of the nuclear potential and pairing corrections have been examined to energies up to 100 MeV. The results were obtained using energy dependent single particle level density or the non equi-distant spacing model. Comparisons are made by adding some and full combination of the corrections to get an accurate and convenient choice in pre-equilibrium state density estimations. The results are compared with available experimental （Oslo）, and theoretical （HF-BCS） results. Results have been found matching the previously obtained experimental and theoretical results.
基金Project supported by the National Natural Science Foundations of China (Grant Nos O69C041001 and 2007CB924904)
文摘This paper studies the size dependence of biexciton binding energy in single quantum dots （QDs） by using atomic force microscopy and micro-photoluminescence measurements. It finds that the biexciton binding energies in the QDs show ＂binding＂ and ＂antibinding＂ properties which correspond to the large and small sizes of QDs, respectively. The experimental results can be well interpreted by the biexciton potential curve, calculated from the exciton molecular model and the Heitler London method.
基金Project supported by the Serbian Ministry of Education and Science(Grant No.OI-171009)the Provincial Secretariat for High Education and Scientific Research of Vojvodina(Grant No.APV 114-451-2201).
文摘The exciton dispersion is examined in the case of four selected prototypical molecular solids: pentacene, tetracene, picene, and chrysene. The model parameters are determined by fitting to experimental data obtained by inelastic electron scattering. Within the picture that relies on Frenkel-type excitons we obtain that theoretical dispersion curves along different directions in the Brillouin zone are in good agreement with the experimental data, suggesting that the influence of charge-transfer excitons on exciton dispersion of the analyzed organic solids is not as large as proposed. In reciprocal space directions where Davydov splitting is observed we employ the upgraded version of Hamiltonian used in Materials 11, 2219 (2018).
基金supported by IAEA Coordinated Research Projects (CRPs) on Parameters for Calculation of Nuclear Reactions of Relevance to Non-energy Nuclear Applications under Grant No.12842/R2
文摘Based on the theoretical models for light nuclei, the calculations of reaction cross sections and the angular distributions for d ＋^8Li reaction are performed. Since all of the particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism is taken into account. The three- body break-up process and the recoil effect are involved. The theoretical calculated results are compared to existing experimental data.
文摘(n,a)反应截面对于反应堆,特别是对快堆和聚变堆工程设计是一种很重要的数据。在一些近似条件下,基于核反应蒸发和预平衡激子模型理论研究了入射能量小于 20 MeV的(n,a)激发函数。在靶核30≤A≤209 范围内,基于(n,a)反应的截面实验数据对得到的半经验公式的参数进行了研究,得到了参数对靶核的 N 和 Z 以及中子入射能量的依赖关系。利用普适参数预言(n,a)反应的激发函数,预言值在其误差范围内与实验数据一致。
基金This work was supported by the Zhejiang Provincial Natural Science Foundation of China （No.LY13A040006）, and the K. C. Wong Magna Foundation in Ningbo University.
文摘We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.
