LiNiO2 (LNO)基态的晶体结构和电子结构长期以来存在着实验与理论计算不一致的争议. 实验上观测到LNO是空间群为 $$R\overline3m$$ 的半导体并且有局部的Jahn-Teller (JT)畸变, 但理论计算却表明它是处于亚稳态的金属并且没有任何的JT畸变. 本文基于杂化密度泛函理论HSE06, 首次模拟了与实验等同浓度(~3%)的Ni/Li反位缺陷对LNO的影响, 发现缺陷能够有效调控LNO中的JT效应. 在LNO中引入Ni/Li反位缺陷后, 其结构发生了局部的JT畸变, 并且其带隙值约为0.5 eV, 这些计算结果都和实验现象非常吻合. Ni/Li反位通过粒径效应和库伦作用, 既能诱发JT畸变, 又能阻碍畸变之间的协同作用, 避免相变到C2/m, 而只产生局部的JT畸变. 本文提出了一种新的策略来解释LNO基态晶体结构和电子结构长期以来的争议, 对推动富镍层状材...

It is shown that the layered antiferromagnetic order in stoechiometric LaMnO3 cannot be understood purely from electronic interactions. On the contrary, it mainly results from strong cooperative Jahn-Teller deformation. Those involve a compression of the Mn−O octahedron along the c−axis (mode Q3 < 0), while alternate Jahn-Teller deformations occur in the ab−plane (mode Q2). These deformations s...

The Jahn-Teller effect in the first two excited states of the nitrate radical NO3 has yet to be experimentally elucidated. In this paper, direct evidence of strong Jahn-Teller interactions in the A state is presented from the first complete absorption spectrum of the A2E'' <-- X2A(2)' transition of NO3 in the gas phase in the region 5900-9000 cm(-1), at moderate resolution (0.15 cm(-1)). The ob...

The ground and low-lying electronic states of the 1,3,5-tridehydrobenzene triradical are characterized by electronic structure calculations. It is found that the ground state is the A1 doublet of C2v symmetry. Another doublet state lies 0.1–0.2 eV higher in energy, and the lowest quartet state of D3h symmetry is 1.2–1.4 eV higher in energy. Both doublets are degenerate at D3h geometries and und...

A simple, yet accurate solution of the electron–phonon coupling problem in C 60 is presented. The basic idea behind it is to be found in the parametrization of the ground state electronic density of the system calculated making use of ab–initio methods, in term of sp 2+x hybridized orbitals. This parametrization allows for an economic determination of the deformation potential associated with t...