Chemical Calculation in the Laboratory

Conformational mobility of tetruloses, 2-pentuloses, D-3-pentulose and 4-deoxy-L-pentulose was studied by measuring temperature dependences of CD spectra in the region +40°C to -140°C in a methanol-ethanol (1:4) mixture. The changes in spectra reflect the population of rotamers around bonds to the carbonyl chromophore. The most stable conformers were determined by PCILO quantum chemical calculation.

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Jahn-Teller Effect in Hexahydroxocuprate(II) Complexes

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19951429 ◽

1995 ◽

Vol 60 (9) ◽

pp. 1429-1434

Author(s):

Martin Breza

Keyword(s):

Hydrogen Bonding ◽

Quantum Chemical ◽

Potential Surface ◽

Hydroxyl Group ◽

Chemical Calculation ◽

Teller Distortion ◽

Jahn Teller ◽

Jahn Teller Effect ◽

Extremal Values ◽

Jahn Teller Distortion

Using semiempirical CNDO-UHF method the adiabatic potential surface of 2[Cu(OH)6]4- complexes is investigated. The values of vibration and vibronic constants for Eg - (a1g + eg) vibronic interaction attain extremal values for the optimal O-H distance. The Jahn-Teller distortion decreases with increasing O-H distance. The discrepancy between experimentally observed elongated bipyramid of [Cu(OH)6]4- in Ba2[Cu(OH)6] and the compressed one obtained by quantum-chemical calculation is explainable by hydrogen bonding of the axial hydroxyl group.

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ChemInform Abstract: QUANTUM CHEMICAL CALCULATION ON THE MOLECULAR STRUCTUR OF PHENYLENE DIAMINES AND N-SILYL-PHENYLENE DIAMINES

Chemischer Informationsdienst ◽

10.1002/chin.197408087 ◽

1974 ◽

Vol 5 (8) ◽

Author(s):

J. NAGY ◽

P. HENCSEI

Keyword(s):

Quantum Chemical Calculation ◽

Quantum Chemical ◽

Chemical Calculation

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Nanostructured Palladacycle and its Decorated Ag-NP Composite: Synthesis, Morphological Aspects, Characterization, Quantum Chemical Calculation and Antimicrobial Activity

Arabian Journal for Science and Engineering ◽

10.1007/s13369-020-05214-x ◽

2021 ◽

Author(s):

N. F. Alotaibi ◽

I. H. Alsohaimi ◽

A. M. Hassan ◽

Modather. F. Hussein ◽

Ahmed E. Taha ◽

...

Keyword(s):

Antimicrobial Activity ◽

Quantum Chemical Calculation ◽

Quantum Chemical ◽

Chemical Calculation ◽

Morphological Aspects ◽

Composite Synthesis

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Improvement of DC Breakdown Strength of the Epoxy/POSS Nanocomposite by Tailoring Interfacial Electron Trap Characteristics

Materials ◽

10.3390/ma14051298 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1298

Author(s):

Farooq Aslam ◽

Zhen Li ◽

Guanghao Qu ◽

Yang Feng ◽

Shijun Li ◽

...

Keyword(s):

Epoxy Resin ◽

Breakdown Voltage ◽

Breakdown Strength ◽

Deep Level ◽

Simulation Method ◽

Neat Epoxy ◽

Interfacial Region ◽

Chemical Calculation ◽

Oligomeric Silsesquioxane ◽

Underlying Risk

To date, breakdown voltage is an underlying risk to the epoxy-based electrical high voltage (HV) equipment. To improve the breakdown strength of epoxy resin and to explore the formation of charge traps, in this study, two types of polyhedral oligomeric silsesquioxane (POSS) fillers are doped into epoxy resin. The breakdown voltage test is performed to investigate the breakdown strength of neat epoxy and epoxy/POSS composites. Electron traps that play an important role in breakdown strength are characterized by thermally stimulated depolarized current (TSDC) measurement. A quantum chemical calculation tool identifies the source of traps. It is found that adding octa-glycidyl POSS (OG-POSS) to epoxy enhances the breakdown strength than that of neat epoxy and epoxycyclohexyl POSS (ECH-POSS) incorporated epoxy. Moreover, side groups of OG-POSS possess higher electron affinity (EA) and large electronegativity that introduces deep-level traps into epoxy resin and restrain the electron transport. In this work, the origin of traps has been investigated by the simulation method. It is revealed that the functional properties of POSS side group can tailor an extensive network of deep traps in the interfacial region with epoxy and enhance the breakdown strength of the epoxy/POSS nanocomposite.

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