Characterization of the High-Pressure Structural Transition and Thermodynamic Properties in Sodium Chloride: A Computational Investigation on the Basis of the Density Functional Theory

2008 ◽  
Vol 112 (44) ◽  
pp. 13898-13905 ◽  
Author(s):  
Cheng Lu ◽  
Xiao-Yu Kuang ◽  
Qin-Sheng Zhu
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Sodium Chloride ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Structural Transition ◽  
Computational Investigation ◽  
Functional Theory ◽  
The Density Functional Theory

Density functional theory (DFT) calculations on the structures and stabilities of [CnO2n+1]2– and [CnO2n+1]X2 polycarbonates containing chainlike (CO2)n units (n = 2–6; X = H or Li)

2011 ◽  
Vol 89 (6) ◽  
pp. 671-687 ◽  
Author(s):  
Pablo J. Bruna ◽  
Friedrich Grein ◽  
Jack Passmore
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ion Pairs ◽  
Dicarboxylic Acids ◽  
Polarizable Continuum Model ◽  
Weakly Bound ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Weakly Bound Complexes

The structures and stabilities of chainlike (CO2)n (n = 2–6) polycarbonates, where adjacent C atoms are linked by C–O–C bonds, were investigated at the density functional theory (DFT) level (B3PW91/6–311G(2d,p)), including dicarboxylic dianions, [CnO2n+1]2–, and the corresponding acids, [CnO2n+1]H2, and Li salts, [CnO2n+1]Li2. At equilibrium, the most stable systems have Cs, C2, or C2v symmetries. In the gas phase, these dianions are generally metastable with respect to spontaneous ejection of one electron, yet in the presence of counterions they become stabilized, for example, as [CnO2n+1]2–(Li+)2 ion pairs. [CnO2n+1]2– linkages are also stabilized as dicarboxylic acids, [CnO2n+1]H2; we find the latter to have equilibrium conformations of higher symmetry than previously reported in the literature. To the best of our knowledge, none of the [CnO2n+1]X2 (X = Li or H) compounds with n ≥ 2 have been reported in the experimental literature (albeit, the alkyl esters C2O5R2 and C3O7R2 are commercially available). All CO bonds in C2O5X2 to C6O13X2 have single- to double-bond character (≈140–118 pm), indicating that the [CnO2n+1] moieties are held together by strong chemical forces (in contrast to the weakly bound complexes (CO2)n and (CO2)n–, n > 1). Vibrational frequencies were calculated to ensure all conformations were true minima. The IR and Raman intensities show that the high intensity C=O stretching modes (1750 ± 100 cm–1) will help in the spectral characterization of these compounds. Solvation calculations using the polarizable continuum model (PCM) find that C2O52– can be formed via CO32– + CO2 as well as CO3–[Formula: see text], each reaction having ΔG298 < 0 in practically all solvents. This result confirms the experimentally observed large solubility of CO2(g) in molten carbonates, CO3M2 (M = Li, Na, or K). In contrast, starting with n = 2, the reactions [CnO2n+1]2– + CO2 do not proceed spontaneously in any solvent (ΔG298 > 0).

Structural, elastic and vibrational properties of nanocrystalline lutetium gallium garnet under high pressure

2015 ◽  
Vol 17 (14) ◽  
pp. 9454-9464 ◽  
Author(s):  
V. Monteseguro ◽  
P. Rodríguez-Hernández ◽  
H. M. Ortiz ◽  
V. Venkatramu ◽  
F. J. Manjón ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Ab Initio ◽  
Density Functional ◽  
Vibrational Properties ◽  
Functional Theory ◽  
The Density Functional Theory

An ab initio study of the structural, elastic and vibrational properties of the lutetium gallium garnet (Lu3Ga5O12) under pressure has been performed in the framework of the density functional theory, up to 95 GPa.

Density Functional Theory Investigation and Detonation Characterization of DNPDNAZ

2014 ◽  
Vol 997 ◽  
pp. 264-267
Author(s):  
Hong Ya Li ◽  
Tian Tian Zhang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Dft Method ◽  
Detonation Pressure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Equivalent Equation ◽  
Molecular Reactivity ◽  
Density Results

N-2’,4’-dinitrophenyl-3,3-dinitroazetidine (DNPDNAZ) is an important derivative of 3,3-dinitroazetidine (DNAZ). The density functional theory (DFT) method of the Amsterdam density functional (ADF) was used to calculate the geometry and frequencies. The detonation velocity (D) and detonation pressure (P) of DNPDNAZ were estimated using the nitrogen equivalent equation according to the experimental density. Results showed that the initial decomposition step of DNPDNAZ is the loss of NO2from C2 and N1 is the point of molecular reactivity,DandPare 7364.42 m·s-1and 23.75 GPa, respectively.

Sign in / Sign up

Export Citation Format

Share Document