Tsallis q ‐exponentials as atomic orbitals in two‐electron systems

Author(s):  
Giuseppe Marcello Lombardo
1985 ◽  
Vol 32 (12) ◽  
pp. 8377-8380 ◽  
Author(s):  
Y. P. Li ◽  
Zong-Quan Gu ◽  
W. Y. Ching

1968 ◽  
Vol 10 (4) ◽  
pp. 364-366 ◽  
Author(s):  
J. A. Chapman ◽  
D. P. Chong

2021 ◽  
Author(s):  
Sunghun Kim ◽  
Joonho Bang ◽  
Chan-young Lim ◽  
Seung Yong Lee ◽  
Jounghoon Hyun ◽  
...  

Abstract Pure quantum electrons render intriguing correlated electronic phases by virtue of quantum fluctuations in addition to an exclusive electron-electron interaction. To realise such quantum electron systems, a key ingredient is dense electrons decoupled from other degrees of freedom. Here, we report the discovery of a pure quantum electron liquid, which spreads up to ~ 3 Å in the vacuum on the surface of electride crystal. An extremely high electron density and its scant hybridization with underneath atomic orbitals evidence quantum and pure nature of electrons, exhibiting polarized liquid phase demonstrated by spin-dependent measurement. Further, upon reducing the density, the dynamics of quantum electrons drastically changes to that of non-Fermi liquid along with an anomalous band deformation, manifesting a possible transition to a hexatic liquid crystalline phase. Our findings cultivate the frontier of quantum electron systems, which serve as an ideal platform for exploring the correlated electronic phases in a pure manner.


2021 ◽  
Vol 6 (4) ◽  
pp. 46
Author(s):  
Levan Chkhartishvili

Atoms are proved to be semi-classical electronic systems in the sense of closeness of their exact quantum electron energy spectrum with that calculated within semi-classical approximation. Introduced semi-classical model of atom represents the wave functions of bounded in atom electrons in form of hydrogen-like atomic orbitals with explicitly defined effective charge numbers. The hydrogen-like electron orbitals of constituting condensed matter atoms are used to calculate the matrix elements of the secular equation determining the condensed matter electronic structure in the linear-combination-of-atomic-orbitals (LCAO) approach. Preliminary test calculations are conducted for boron B atom and diboron B2 molecule electron systems. 


Author(s):  
Xudong Weng ◽  
O.F. Sankey ◽  
Peter Rez

Single electron band structure techniques have been applied successfully to the interpretation of the near edge structures of metals and other materials. Among various band theories, the linear combination of atomic orbital (LCAO) method is especially simple and interpretable. The commonly used empirical LCAO method is mainly an interpolation method, where the energies and wave functions of atomic orbitals are adjusted in order to fit experimental or more accurately determined electron states. To achieve better accuracy, the size of calculation has to be expanded, for example, to include excited states and more-distant-neighboring atoms. This tends to sacrifice the simplicity and interpretability of the method.In this paper. we adopt an ab initio scheme which incorporates the conceptual advantage of the LCAO method with the accuracy of ab initio pseudopotential calculations. The so called pscudo-atomic-orbitals (PAO's), computed from a free atom within the local-density approximation and the pseudopotential approximation, are used as the basis of expansion, replacing the usually very large set of plane waves in the conventional pseudopotential method. These PAO's however, do not consist of a rigorously complete set of orthonormal states.


Author(s):  
Shiwei Wang ◽  
Anton Chavez ◽  
Simil Thomas ◽  
Hong Li ◽  
Nathan C. Flanders ◽  
...  

This work reports on the assembly of imine-linked macrocycles that serve as models of two-dimensional covalent organic frameworks (2D COFs). Interlayer interactions play an important role in the formation of 2D COFs, yet the effect of monomer structure on COF formation, crystallinity, and susceptibility to exfoliation are not well understood. For example, monomers with both electron-rich and electron-poor π-electron systems have been proposed to strengthen interlayer inter-actions and improve crystallinity. Here we probe these effects by studying the stacking behavior of imine-linked macrocycles that represent discrete models of 2D COFs. <div><br></div><div>Specifically, macrocycles based on terephthaldehyde (PDA) or 2,5-dimethoxyterephthaldehyde (DMPDA) stack upon cooling molecularly dissolved solutions. Both macrocycles assemble cooperatively with similar ΔHe values of -97 kJ/mol and -101 kJ/mol, respectively, although the DMPDA macrocycle assembly process showed a more straightforward temperature dependence. Circular dichroism spectroscopy performed on macrocycles bearing chiral side chains revealed a helix reversion process for the PDA macrocycles that was not observed for the DMPDA macrocycles. <br></div><div><br></div><div>Given the structural similarity of these monomers, these findings demonstrate that the stacking processes associated with nanotubes derived from these macrocycles, as well as for the corresponding COFs, are complex and susceptible to kinetic traps, casting doubt on the relevance of thermodynamic arguments for improving materials quality. <br></div>


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