Theoretical enthalpies of formation and structural characterisation of halogenated nitromethanes and isomeric halomethyl nitrites

2012 ◽  
Vol 66 (12) ◽  
Author(s):  
Agnie Kosmas ◽  
Aristeidis Ntivas ◽  
Stavroula Liaska ◽  
Demetrios Papayannis
Keyword(s):  
Density Functional ◽  
Strong Dependence ◽  
Enthalpies Of Formation ◽  
Induction Effect ◽  
Functional Theory ◽  
Structural Characterisation ◽  
Dissociation Energies ◽  
Species Formation ◽  
Stable Species ◽  
Formation Enthalpies

AbstractThe structural, energetic, and thermochemical properties of a number of halogenated nitromethanes, CHnX3−n NO2, and the isomeric nitrites, CHnX3−n ONO, are investigated, using theoretical ab initio and density functional theory (DFT) electronic structure methods. Analysis of the results and comparison with the maternal species, nitromethane, CH3NO2, and methyl nitrite, CH3ONO, reveal strong dependence of the molecular properties on the halogen induction effect. Opposite trends are obtained in the C—N and C—O bond dissociation energies (BDE) upon halogenation and higher stabilities are calculated for the trans-nitrite isomers, in contrast with the plain alkyl families where the nitroalkanes are the most stable species. Formation enthalpies, ΔH fℴ, at 298 K are calculated for all halogenated isomers.

scholarly journals Quantum molecular dynamics investigations of protactinium (V) fluoro and oxofluoro complexes in solution

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Bruno Siberchicot ◽  
Jean Aupiais ◽  
Claire Le Naour
Keyword(s):  
Molecular Dynamics ◽  
Gas Phase ◽  
Software Package ◽  
Density Functional ◽  
Water Molecules ◽  
Quantum Molecular Dynamics ◽  
Functional Theory ◽  
Dissociation Energies ◽  
Formation Enthalpies ◽  
Dynamics Simulations

Abstract Quantum Molecular Dynamics simulations of protactinium (V) fluoro and oxofluoro complexes in solution were undertaken using density functional theory with generalised gradient approximation (and the ABINIT software package). The complexes were studied in the gas phase (at 0 K) and in solution (at 298 K) with water molecules as the solvent. We characterised all of the systems, taking into account their structures, dissociation energies, bond lengths and formation enthalpies in solution, and explained their relative stabilities. At ambient temperature, the hydrated species PaF 5, P a F 4 + $Pa{F}_{4}^{+}$ , P a O F 5 2 − $PaO{F}_{5}^{2-}$ , P a O F 4 − $PaO{F}_{4}^{-}$ and PaOF 3 were found to be the most stable (and to exhibit similar stabilities). The calculated formation enthalpies of the complexes are in close agreement with measurements made elsewhere.

Enthalpies of Formation of Dibenzo-p-dioxin and Polychlorinated Dibenzo-p-dioxins Calculated by Density Functional Theory

2003 ◽  
Vol 107 (16) ◽  
pp. 2848-2854 ◽  
Author(s):  
Olga V. Dorofeeva ◽  
Vladimir S. Yungman
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Enthalpies Of Formation ◽  
Functional Theory

scholarly journals Density functional theory studies on the dissociation energies of metallic salts: Relationship between lattice and dissociation energies

2002 ◽  
Vol 23 (5) ◽  
pp. 584-584 ◽  
Author(s):  
Chang Kon Kim ◽  
Hongok Won ◽  
Hoon Sik Kim ◽  
Yong Soo Kang ◽  
Hong Guang Li ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Dissociation Energies ◽  
Metallic Salts

First-principles density-functional-theory calculations of formation and dissociation energies in germanene multivacancies

2020 ◽  
Vol 22 ◽  
pp. 100754 ◽  
Author(s):  
Dian Putri Hastuti ◽  
Wardah Amalia ◽  
Zakiah Priska ◽  
Pekik Nurwantoro ◽  
Sholihun
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Dissociation Energies

scholarly journals Development of a CALPHAD Thermodynamic Database for Pu-U-Fe-Ga Alloys

2019 ◽  
Vol 9 (23) ◽  
pp. 5040 ◽  
Author(s):  
Emily E. Moore ◽  
Patrice E.A. Turchi ◽  
Alexander Landa ◽  
Per Söderlind ◽  
Benoit Oudot ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Density Functional ◽  
Ternary Phase Diagram ◽  
Thermodynamic Database ◽  
Impurity Effects ◽  
Functional Theory ◽  
Formation Enthalpies ◽  
Temperature Ranges ◽  
The Stability ◽  
First Time

The interaction of actinides and actinide alloys such as the δ-stabilized Pu-Ga alloy with iron is of interest to understand the impurity effects on phase stability. A newly developed and self-consistent CALPHAD thermodynamic database is presented which covers the elements: Pu, U, Fe, Ga across their whole composition and temperature ranges. The phase diagram and thermodynamic properties of plutonium-iron (Pu-Fe) and uranium-iron (U-Fe) systems are successfully reassessed, with emphasis on the actinide rich side. Density functional theory (DFT) calculations are performed to validate the stability of the stoichiometric (Pu,U)6Fe and (Pu,U)Fe2 compounds by computing their formation enthalpies. These data are combined to construct the Pu-U-Fe ternary phase diagram. The thermodynamic assessment of Fe-Ga is presented for the first time and application to the quaternary Pu-U-Fe-Ga system is discussed.

The Theory Investigation for the Antioxidant Activity of Phloretin: A Comparation with Naringenin

2014 ◽  
Vol 513-517 ◽  
pp. 359-362
Author(s):  
Ming Xun Yan ◽  
Jin Dong Gong ◽  
Ping Shen ◽  
Chang Ying Yang
Keyword(s):  
Density Functional Theory ◽  
Antioxidant Activity ◽  
Density Functional ◽  
Radical Scavenging ◽  
Basis Set ◽  
Hydroxyl Groups ◽  
Bond Dissociation Energies ◽  
Functional Theory ◽  
Dissociation Energies ◽  
Radical Scavenging Properties

Density functional theory (DFT) calculations, based on B3LYP/6-311G (d, p) basis set, were performed to evaluate the OH bond dissociation energies (BDEs) for phloretin, compared with naringenin, in order to assess the contribution of hydroxyl groups at different position to the radical-scavenging properties. It is indicated clearly that A6 OH is determined as the weakest O-H bond, give rise to the smallest BDE, 73.98 kcal/mol. BDE of B4 OH decreases 2.5 kcal/mol in benzene, very close to that of A6OH, indicated that B4 OH group is also mainly contributed to the reaction with free radicals, especially in non-polar environments.

EMPIRICAL METHODS FOR ESTIMATING THE DETONATION PROPERTIES OF ENERGETIC TNAZ MOLECULAR DERIVATIVES

2004 ◽  
Vol 03 (03) ◽  
pp. 379-389 ◽  
Author(s):  
MIN-HSIEN LIU ◽  
CHENG CHEN ◽  
YAW-SHUN HONG
Keyword(s):  
Density Functional ◽  
Dft Calculation ◽  
Enthalpies Of Formation ◽  
Detonation Properties ◽  
Group Additivity ◽  
Detonation Pressure ◽  
Empirical Methods ◽  
Functional Theory ◽  
Simulation Results ◽  
Hybrid Density Functional

Following the successful synthesis of the TNAZ (1,3,3-trinitroazetidine), the amine reactant is theoretically replaced to yield the hypothesized TNAZ molecular derivatives. Hybrid density-functional theory (DFT) calculation method was applied to model TNAZ and its derivatives. In this investigation, the target molecular volumes were initially obtained using the group additivity approach, and then transferred into molecular densities. The densities and the least squares estimated enthalpies of formation (ΔHf) of TNAZ, and the corresponding derivatives, were obtained and the Kamlet–Jacobs empirical equations were used to determine the related detonation velocity and detonation pressure. The simulation results reveal that four of the TNAZ molecular derivatives perform similarly to the traditionally used RDX (1,3,5-trinitro-1,3,5-triazacyclohexane). Two other derivatives outperform RDX, with performance that approach that of HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane).

THEORETICAL STUDIES ON BOND DISSOCIATION ENERGIES FOR SOME THIOL COMPOUNDS BY DENSITRY FUNCTIONAL THEORY AND CBS-Q METHOD

2008 ◽  
Vol 07 (05) ◽  
pp. 943-951 ◽  
Author(s):  
XIAO-HONG LI ◽  
ZHENG-XIN TANG ◽  
ABRAHAM F. JALBOUT ◽  
XIAN-ZHOU ZHANG ◽  
XIN-LU CHENG
Keyword(s):  
Density Functional ◽  
Computational Cost ◽  
Basis Set ◽  
Basis Sets ◽  
Q Method ◽  
Bond Dissociation Energies ◽  
Functional Theory ◽  
Thiol Compounds ◽  
Bond Dissociation ◽  
Dissociation Energies

Quantum chemical calculations are used to estimate the bond dissociation energies (BDEs) for 15 thiol compounds. These compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86, PBE0) methods and the complete basis set (CBS-Q) method together with 6-311G** basis set. It is demonstrated that B3P86 and CBS-Q methods are accurate for computing the reliable BDEs for thiol compounds. In order to test whether the non-local BLYP method suggested by Fu et al.19 is general for our study and whether B3P86 method has a low basis set sensitivity, the BDEs for seven thiol compounds are also calculated using BLYP/6-31+G* and B3P86 method with 6-31+G*, 6-31+G**, and 6-311+G** basis sets for comparison. The obtained results are compared with the available experimental results. It is noted that B3P86 method is not sensitive to the basis set. Considering the inevitable computational cost of CBS-Q method and the reliability of the B3P86 calculations, B3P86 method with a moderate or a larger basis set may be more suitable to calculate the BDEs of the C–SH bond for thiol compounds.

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