scholarly journals Density Functional Study of Structures and Electron Affinities of BrO4F/BrO4F-

2009 ◽  
Vol 10 (7) ◽  
pp. 3128-3148 ◽  
Author(s):  
Liangfa Gong ◽  
Jieming Xiong ◽  
Xinmin Wu ◽  
Chuansong Qi ◽  
Wei Li ◽  
...  
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Basis Sets ◽  
Functional Study ◽  
Bond Dissociation Energies ◽  
Electron Affinities ◽  
Dft Methods ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
B3lyp Method

The structures, electron affinities and bond dissociation energies of BrO4F/BrO4F− species have been investigated with five density functional theory (DFT) methods with DZP++ basis sets. The planar F-Br…O2…O2 complexes possess 3A' electronic state for neutral molecule and 4A' state for the corresponding anion. Three types of the neutral-anion energy separations are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The EAad value predicted by B3LYP method is 4.52 eV. The bond dissociation energies De (BrO4F → BrO4-mF + Om) (m = 1-4) and De- (BrO4F- → BrO4-mF- + Om and BrO4F- → BrO4-mF + Om-) are predicted. The adiabatic electron affinities (EAad) were predicted to be 4.52 eV for F-Br…O2…O2 (3A'← 4A') (B3LYP method).

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.

Assessment of PBE0 Calculation of C-NO2 Bond Dissociation Energies for Nitroaromatic System

2014 ◽  
Vol 915-916 ◽  
pp. 675-678
Author(s):  
Xin Fang Su ◽  
Wei Huang ◽  
Hai Ying Wu
Keyword(s):  
Density Functional ◽  
Molecular System ◽  
Absolute Error ◽  
Basis Sets ◽  
Bond Dissociation Energies ◽  
Average Absolute Error ◽  
Functional Theory ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Experimental Values

Density functional theory (DFT) is used to calculate the C-NO2bond dissociation energies (BDEs) in nitrobenzene; 3-amino-nitrobenze; 4-amino-nitrobenze; 1,3-dinitrobenzene; 1,4-dinitrobenzene; 2-methyl-nitrobenzene; 4-methyl-nitrobenzene and 1,3,5-trinitrobenzene nitroaromatic molecular system. B3P86 and PBE0 methods in combination with 6-31G** and 6-311G** basis sets are employed. Comparison between the computational results and the experimental values reveals that the calculated C-NO2bond BDEs can be improved from B3P86 to PBE0 functional. Level of theory employing PBE0/6-311G** is found to be sufficiently reliable to compute BDEs of C-NO2bond for nitroaromatic molecules with an average absolute error of 0.98 kcal mol-1.

THEORETICAL STUDIES ON BOND DISSOCIATION ENERGIES FOR SOME ALIPHATIC ALCOHOL COMPOUNDS BY DENSITY FUNCTIONAL THEORY AND CBS-Q METHOD

2011 ◽  
Vol 10 (02) ◽  
pp. 179-189 ◽  
Author(s):  
XIAO-HONG LI ◽  
GENG-XIN YIN ◽  
XIAN-ZHOU ZHANG
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Aliphatic Alcohol ◽  
Basis Set ◽  
Basis Sets ◽  
Q Method ◽  
Bond Dissociation Energies ◽  
Functional Theory ◽  
Bond Dissociation ◽  
Dissociation Energies

Quantum chemical calculations are used to estimate the bond dissociation energies (BDEs) for 20 aliphatic alcohol compounds. These compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, and B3P86) methods with 6-311G** basis set and the complete basis set (CBS-Q) method together. It is demonstrated that B3P86 and CBS-Q methods are accurate to compute the reliable BDEs for aliphatic alcohol compounds. In order to test whether the non-local BLYP method suggested by Jursic18 is general for our study and whether B3P86 method has a low basis set sensitivity, the BDEs for 20 aliphatic alcohol compounds are also calculated using BLYP/6-31+G*, BLYP/6-31G*, and B3P86 methods with 6-31G*, 6-31+G*, and 6-31G** basis sets for comparison. The obtained results are compared with the available experimental results. It is noted that B3P86 method is sensitive to the basis sets. Considering the inevitably computational cost of CBS-Q method and the reliability of the B3P86 calculation, B3P86 method with 6-31G** basis set may be more suitable to calculate the BDEs of the C–O bond for aliphatic alcohol compounds.

Polarized continuum model study of bond dissociation energies of the O–NO2 bond — A density functional theory study and natural bond order analysis

2012 ◽  
Vol 90 (5) ◽  
pp. 433-440
Author(s):  
Zhang Ruizhou ◽  
Fu Zhumu ◽  
Li Xiaohong ◽  
Zhang Xianzhou
Keyword(s):  
Density Functional ◽  
Parent Compound ◽  
Substituent Effects ◽  
Accurate Method ◽  
Basis Sets ◽  
Acetonitrile Solution ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Polarized Continuum Model

Density functional methods (B3LYP, B3PW91, B3P86, and MPWB95) with 6–31G** basis sets and complete basis methods are employed to investigate the bond dissociation energies (BDEs) of the O–NO2 bond for seven O-nitroalcohol compounds in acetonitrile solution. B3LYP/6–31+G**, (RO)B3LYP/6–311++G(2df,2p), and B3LYP/6–311G(d,p) methods are also used. By comparing the calculated results with the experimental values, B3LYP/6–31+G** is the most accurate method to compute the reliable BDEs for the studied compounds. The substituent effects on the O–NO2 BDEs are analyzed. It is found that electron-withdrawing groups increase the BDE of the parent compound, whereas electron-donating groups decrease the BDE of the parent compound. Further, the natural bond orbital analysis shows that there exist good linear correlations between E(2) and Hammett constants, the BDE, and the difference of the second-order stabilization energies E(2) of lpO3 → BD*(O1–N1) and lpO3 → BD*(O2–N1).

The DFT Quantum Chemistry Study of Hexafluorobenzene

2012 ◽  
Vol 610-613 ◽  
pp. 106-110
Author(s):  
Hui Yi Pei ◽  
Ai Fang Gao ◽  
Zhen Ya Zhu
Keyword(s):  
Electron Affinity ◽  
Density Functional ◽  
Molecular Structures ◽  
Basis Set ◽  
Electron Affinities ◽  
Dft Methods ◽  
Dissociation Energies ◽  
Theoretical Predictions ◽  
Vertical Detachment Energy ◽  
Vertical Electron Affinity

The molecular structures, electron affinities, and dissociation energies of the C6F6molecule have been determined using seven hybrid and pure density functional theory (DFT) methods and the DZP++ basis set. Three different types of the neutral-anion energy separations reported in this work are the adiabatic electron affinity (EAad), the vertical electron affinity (EAvert), and the vertical detachment energy (VDE). The most reliable adiabatic electron affinities, obtained at the B3PW91 and B3LYP levels, are 0.59 and 0.69 eV, respectively. The first dissociation energies De(C6F5-F) for the neutral C6F6predicted by the DFT methoSubscript textds except BHLYP are 5.195.44 eV. Compared with the limited experimental dissociation energies, our theoretical predictions of the B3LYP and B3PW91 methods are fairly reasonable.

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