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The Structure of Essential Spectra and Discrete Spectrum of Three-Electron Systems in the Impurity Hubbard Model—Quartet State 被引量:3
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作者 S. M. Tashpulatov 《Journal of Applied Mathematics and Physics》 2021年第6期1391-1421,共31页
We consider a three-electron system in the Impurity Hubbard model with a coupling between nearest-neighbors. Our research aim consists of studying the structure of essential spectrum and discrete spectra of the energy... We consider a three-electron system in the Impurity Hubbard model with a coupling between nearest-neighbors. Our research aim consists of studying the structure of essential spectrum and discrete spectra of the energy operator of three-electron systems in the impurity Hubbard model in the quartet state of the system in a <em>v</em>-dimensional lattice. We have reduced the study of the spectrum of the three-electron quartet state operator in the impurity Hubbard model to the study of the spectrum of a simpler operator. We proved the essential spectra of the three-electron systems in the Impurity Hubbard model in the quartet state is the union of no more than six segments, and the discrete spectrum of the system is consists of no more than four eigenvalues. 展开更多
关键词 Essential Spectrum Discrete Spectrum Three-Electron System Local Impurity states Impurity Hubbard Model quartet state Doublet state
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Structure of Essential Spectrum and Discrete Spectra of the Energy Operator of Five-Electron Systems in the Hubbard Model. Third and Fourth Doublet States 被引量:1
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作者 S. M. Tashpulatov 《Journal of Applied Mathematics and Physics》 2020年第12期2886-2918,共33页
We consider a five-electron system in the Hubbard model with a coupling between nearest-neighbors. The structure of essential spectrum and discrete spectrum of the systems in the third and fourth doublet states in a &... We consider a five-electron system in the Hubbard model with a coupling between nearest-neighbors. The structure of essential spectrum and discrete spectrum of the systems in the third and fourth doublet states in a <em>v</em>-dimensional lattice is investigated. We prove that the essential spectrum of the system in a third doublet state consists is the union of at most four segments, and discrete spectrum of the system is empty. We show that the essential spectrum of the system in a fourth doublet state consists of the union of at most seven segments, and discrete spectrum of the system consists of no more than one point. 展开更多
关键词 Essential Spectrum Discrete Spectrum Five-Electron System Bound state Anti-Bound state Hubbard Model Doublet state Sextet state quartet state
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RAD-seq data reveals robust phylogeny and morphological evolutionary history of Rhododendron
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作者 Yuanting Shen Gang Yao +6 位作者 Yunfei Li Xiaoling Tian Shiming Li Nian Wang Chengjun Zhang Fei Wang Yongpeng Ma 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第3期866-878,共13页
Rhododendron is famous for its high ornamental value.However,the genus is taxonomically difficult and the relationships within Rhododendron remain unresolved.In addition,the origin of key morphological characters with... Rhododendron is famous for its high ornamental value.However,the genus is taxonomically difficult and the relationships within Rhododendron remain unresolved.In addition,the origin of key morphological characters with high horticulture value need to be explored.Both problems largely hinder utilization of germplasm resources.Most studies attempted to disentangle the phylogeny of Rhododendron,but only used a few genomic markers and lacked large-scale sampling,resulting in low clade support and contradictory phylogenetic signals.Here,we used restriction-site associated DNA sequencing(RAD-seq)data and morphological traits for 144 species of Rhododendron,representing all subgenera and most sections and subsections of this species-rich genus,to decipher its intricate evolutionary history and reconstruct ancestral state.Our results revealed high resolutions at subgenera and section levels of Rhododendron based on RAD-seq data.Both optimal phylogenetic tree and split tree recovered five lineages among Rhododendron.Subg.Therorhodion(cladeⅠ)formed the basal lineage.Subg.Tsutsusi and Azaleastrum formed cladeⅡand had sister relationships.CladeⅢincluded all scaly rhododendron species.Subg.Pentanthera(cladeⅣ)formed a sister group to Subg.Hymenanthes(cladeⅤ).The results of ancestral state reconstruction showed that Rhododendron ancestor was a deciduous woody plant with terminal inflorescence,ten stamens,leaf blade without scales and broadly funnelform corolla with pink or purple color.This study shows significant distinguishability to resolve the evolutionary history of Rhododendron based on high clade support of phylogenetic tree constructed by RAD-seq data.It also provides an example to resolve discordant signals in phylogenetic trees and demonstrates the application feasibility of RAD-seq with large amounts of missing data in deciphering intricate evolutionary relationships.Additionally,the reconstructed ancestral state of six important characters provides insights into the innovation of key characters in Rhododend 展开更多
关键词 RHODODENDRON RAD-seq Missing data quartet sampling(QS) Ancestral state reconstruction
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DFT方法对NiB_3结构特性的ab initio计算研究 被引量:3
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作者 方志刚 王娟 《鞍山钢铁学院学报》 1998年第2期1-5,共5页
用DFT方法对NiB3双重态和四重态两种多重度的各种可能构型进行高水平的abinitio计算,发现B原子之间存在较强的相互作用,对NiB3体系的稳定性有很大贡献。
关键词 NiB3 DFT方法 ZPE 单重态 三重态 键级 电荷
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Ni_2B分子结构及成键特性的ab initio计算研究
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作者 方志刚 王娟 《辽宁大学学报(自然科学版)》 CAS 1998年第1期17-21,共5页
本文用DFT方法对Ni2B分子双重态和四重态两种多重度进行高水平的abinitio计算,结果发现B以sp,sp2两种杂化方式同Ni成键,并且B带有相反的电荷;
关键词 硼化镍 分子结构 成键 从头算
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