Zero Band-Gap Polymers:  Quantum-Chemical Study of Electronic Structures of Degenerate π-Conjugated Systems

2000 ◽  
Vol 12 (2) ◽  
pp. 495-500 ◽  
Author(s):  
Sung Y. Hong
Keyword(s):  
Band Gap ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Conjugated Systems

scholarly journals Quantum Chemical Study on Molecular and Electronic Structures of Methyl and Methoxyl Substituted Cu(II) and Ni(II) Benzoic Acid Hydrazides Ions

2010 ◽  
Vol 7 (2) ◽  
pp. 517-525
Author(s):  
I. O. Adeoye ◽  
O. A. Odunola ◽  
M. A. Oladipo ◽  
B. Semire
Keyword(s):  
Hydrogen Bonds ◽  
Benzoic Acid ◽  
Band Gap ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Complex Ions ◽  
Empirical Level ◽  
Semi Empirical

The electronic structures of model methyl and methoxyl substituted benzoic acid hydrazides of Ni(II) and Cu(II) complexes have been studied both at semi empirical level (PM3). Theortho-methoxyl is relatively stable which may be due to the formation of hydrogen bonds between methoxyl oxygen and hydrogen on hydrazide (CH30---HNNH; 1.817Å for Cu(II) and 1.806∼1.839∼ for Ni(II)). The change in torsion in the complexes affectπ-electrons delocalization (complexes containingπ-electrons system) and consequently affect the band gap which is a measure of electronic properties that control the reactivity of the complexes. The curves fororthoandparamethoxyl substituted Cu(II) complexes intercept at 50°and 135°-144°, this could suggest that both complex ions can co-exist and react in very similar ways in solution under certain conditions.

Optical band gap in the system ZnO1 – x S x . An experimental and quantum chemical study

2007 ◽  
Vol 42 (6) ◽  
pp. 1965-1971 ◽  
Author(s):  
S. Locmelis ◽  
C. Brünig ◽  
M. Binnewies ◽  
A. Börger ◽  
K. D. Becker ◽  
...  
Keyword(s):  
Band Gap ◽  
Quantum Chemical ◽  
Optical Band Gap ◽  
Quantum Chemical Study ◽  
Chemical Study

QUANTUM CHEMICAL STUDY OF POLYAROMATIC HYDROCARBONS IN HIGH MULTIPLICITY STATES

2007 ◽  
Vol 21 (26) ◽  
pp. 4507-4515 ◽  
Author(s):  
VOLODYMYR D. KHAVRYUCHENKO ◽  
YURIJ A. TARASENKO ◽  
VOLODYMYR V. STRELKO ◽  
OLEKSIY V. KHAVRYUCHENKO ◽  
VLADYSLAV V. LISNYAK
Keyword(s):  
Ab Initio ◽  
Electronic Structures ◽  
Quantum Chemical ◽  
Polyaromatic Hydrocarbons ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
High Multiplicity ◽  
Ab Initio Methods ◽  
Energetic Stability

A study of polyaromatic hydrocarbons by semiempirical PM3 and ab initio methods in MINI and STO 6G-31 bases has been performed for compounds with different numbers of rings. The optimized space and electronic structures have been derived. The multiplicity states effect on the energetic stability of the polyaromatic hydrocarbons is examined. It is shown that the high multiplicity states become more energetically preferable with the growth of the PAH size.

scholarly journals Quantum-chemical study of octafluoro-spirobi[triphosphazene]

2020 ◽  
Author(s):  
Marian Gall ◽  
Martin Breza
Keyword(s):  
Electronic Structures ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Spin States ◽  
Molecular Charge ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Symmetric Structures ◽  
Stable Structures

The geometries of monocharged and neutral octafluoro-spirobi[triphosphazene] in singlet, doublet and/or triplet ground spin states were optimized. Their electronic structures are investigated in terms of Quantum Theory of Atoms-in-Molecules and compared with neutral hexafluorocyclotriphosphazene. The change of the total molecular charge implies mainly the change of the properties of the nitrogen atoms which are bonded to the central spiro-phosphorus atom. The charged systems in singlet spin states have stable structures of D2d symmetry only unlike the remaining ones of C2 symmetry within two geometry types. The existence of the less symmetric structures can be fully explained as a consequence of the (pseudo-) Jahn-Teller effect.

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