Stationary conditions of the electronic structures against the extension of molecular systems and their application to the elongation method

1993 ◽  
Vol 98 (1) ◽  
pp. 534-542 ◽  
Author(s):  
Koji Maekawa ◽  
Akira Imamura
Keyword(s):  
Electronic Structures ◽  
Molecular Systems ◽  
Elongation Method ◽  
Stationary Conditions

Locality and nonlocality of electronic structures of molecular systems: Toward QM/MM and QM/QM approaches

2012 ◽  
Author(s):  
Shusuke Yamanaka ◽  
Yasushige Yonezawa ◽  
Kazuto Nakata ◽  
Satomichi Nishihara ◽  
Mitsutaka Okumura ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Molecular Systems

scholarly journals Shannon, Rényi, Tsallis Entropies and Onicescu Information Energy for Low-Lying Singly Excited States of Helium

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 70 ◽  
Author(s):  
Jen-Hao Ou ◽  
Yew Kam Ho
Keyword(s):  
Excited States ◽  
Shannon Entropy ◽  
Electronic Structures ◽  
Tsallis Entropy ◽  
Renyi Entropy ◽  
Rényi Entropy ◽  
Electron Delocalization ◽  
Information Theoretic ◽  
Molecular Systems ◽  
Information Energy

Knowledge of the electronic structures of atomic and molecular systems deepens our understanding of the desired system. In particular, several information-theoretic quantities, such as Shannon entropy, have been applied to quantify the extent of electron delocalization for the ground state of various systems. To explore excited states, we calculated Shannon entropy and two of its one-parameter generalizations, Rényi entropy of order α and Tsallis entropy of order α , and Onicescu Information Energy of order α for four low-lying singly excited states (1s2s 1 S e , 1s2s 3 S e , 1s3s 1 S e , and 1s3s 3 S e states) of helium. This paper compares the behavior of these three quantities of order 0.5 to 9 for the ground and four excited states. We found that, generally, a higher excited state had a larger Rényi entropy, larger Tsallis entropy, and smaller Onicescu information energy. However, this trend was not definite and the singlet–triplet reversal occurred for Rényi entropy, Tsallis entropy and Onicescu information energy at a certain range of order α .

Molecular orbitals from group orbitals. I. A perturbational molecular orbital treatment of the electronic structures, shapes and conformations of AHmBHn Systems

1976 ◽  
Vol 54 (6) ◽  
pp. 949-962 ◽  
Author(s):  
Myung-Hwan Whangbo ◽  
Saul Wolfe
Keyword(s):  
Molecular Orbital ◽  
Electronic Structures ◽  
Molecular Orbitals ◽  
Orbital Interaction ◽  
Molecular Systems ◽  
Group Orbitals

A procedure is proposed which allows the group orbitals of a fragment AHm—to be obtained from the molecular orbitals of the molecule AHm—H. Orbital interaction diagrams constructed from these group orbitals have been found useful in the description of the electronic structures and conformations of a variety of molecular systems of the type AHmBHn. The molecules that have been treated by this procedure include ethane, hydrazine, diphosphine, aminophosphine, aminoborane, and sulfonium and phosphonium ylids.

Efficiency and accuracy of the elongation method as applied to the electronic structures of large systems

2006 ◽  
Vol 27 (13) ◽  
pp. 1603-1619 ◽  
Author(s):  
Marcin Makowski ◽  
Jacek Korchowiec ◽  
Feng Long Gu ◽  
Yuriko Aoki
Keyword(s):  
Electronic Structures ◽  
Elongation Method ◽  
Large Systems

An ab initio and density functional theory study on neutral pterin radicals

Pteridines ◽  
2015 ◽  
Vol 26 (4) ◽  
pp. 135-142 ◽  
Author(s):  
Gilbert Reibnegger
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Electronic Structures ◽  
Density Functional ◽  
Electron System ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Molecular Systems ◽  
Phase Water ◽  
Planar Transition

AbstractThe electronic structures of the five radicals resulting from homolytic elimination of one of the hydrogen atoms from the most stable tautomeric form of neutral pterin were investigated in gas phase as well as in aqueous solution. Molecular wave functions obtained by density functional theory were analysed by quantum theory of atoms in molecules and electron localisation functions (ELF). Spin densities of the radicals as well as electrostatic potential functions were analysed. Radicals resulting from elimination of N-bonded hydrogen atoms are more stable in comparison with radicals obtained after abstraction of C-bonded hydrogen atoms. N-centred radicals show strong delocalisation of spin density over both heteroaromatic rings; in C-centred radicals delocalisation does not occur. ELF analyses showed that in N-derived radicals particularly the lone electron pair at N2′ is strongly involved into the bicyclic heteroaromatic π-electron system. Thereby, bonding geometry at N2′ in these radicals changes from pyramidal to planar. Transition from gas phase to solution phase (water) generally leads to increased polarity of the structures. Pterin-derived free radicals have been implicated in several biologically important reactions; so this investigation provides first insights into the detailed electronic structures of such molecular systems.

Sign in / Sign up

Export Citation Format

Share Document