scholarly journals Bond Dissociation Energies of the Tungsten Fluorides and Their Singly Charged Ions:  A Density Functional Survey

2000 ◽  
Vol 104 (17) ◽  
pp. 4077-4083 ◽  
Author(s):  
Kenneth G. Dyall
Keyword(s):  
Density Functional ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Singly Charged ◽  
Charged Ions

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.

scholarly journals An Accurate and Efficient Method to Predict Y-NO Bond Homolysis Bond Dissociation Energies

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Hong Zhi Li ◽  
Lin Li ◽  
Zi Yan Zhong ◽  
Yi Han ◽  
LiHong Hu ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Density Functional ◽  
Molecular Descriptors ◽  
Basis Set ◽  
Bond Dissociation Energies ◽  
Data Set ◽  
Test Set ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Bond Homolysis

The paper suggests a new method that combines the Kennard and Stone algorithm (Kenstone, KS), hierarchical clustering (HC), and ant colony optimization (ACO)-based extreme learning machine (ELM) (KS-HC/ACO-ELM) with the density functional theory (DFT) B3LYP/6-31G(d) method to improve the accuracy of DFT calculations for the Y-NO homolysis bond dissociation energies (BDE). In this method, Kenstone divides the whole data set into two parts, the training set and the test set; HC and ACO are used to perform the cluster analysis on molecular descriptors; correlation analysis is applied for selecting the most correlated molecular descriptors in the classes, and ELM is the nonlinear model for establishing the relationship between DFT calculations and homolysis BDE experimental values. The results show that the standard deviation of homolysis BDE in the molecular test set is reduced from 4.03 kcal mol−1calculated by the DFT B3LYP/6-31G(d) method to 0.30, 0.28, 0.29, and 0.32 kcal mol−1by the KS-ELM, KS-HC-ELM, and KS-ACO-ELM methods and the artificial neural network (ANN) combined with KS-HC, respectively. This method predicts accurate values with much higher efficiency when compared to the larger basis set DFT calculation and may also achieve similarly accurate calculation results for larger molecules.

HOMOLYTIC C–H BOND DISSOCIATION ENERGIES OF HTPB BINDER NETWORK

2009 ◽  
Vol 08 (03) ◽  
pp. 519-528 ◽  
Author(s):  
SONGNIAN LI ◽  
LUOXIN WANG ◽  
YONG LIU ◽  
XINLIN TUO ◽  
XIAOGONG WANG
Keyword(s):  
Density Functional Theory ◽  
Structural Analysis ◽  
Density Functional ◽  
Bond Dissociation Energies ◽  
Functional Theory ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Tertiary Carbon ◽  
Carbon Radicals ◽  
Secondary Carbon

The C – H bond dissociation energies (BDEs) of hydroxyl-terminated polybutadiene (HTPB) binder have been computed using ab initio and density functional theory methods. Five different HTPB carbon radicals were produced by the ruptures of different C – H bonds. The structural analysis of radicals and the calculated BDEs showed that the studied C – H bonds could be divided into three groups. It was found that the weakest C – H bonds were those on the tertiary carbon atom linked to a vinyl function. The next were those on the secondary carbon attached to a vinyl function. The dissociation of these two kinds of C – H bonds determines the structure of the ultimate products during the aging of HTPB binder. The most stable C – H bonds were those in the methylene that were attached to the saturated carbon atoms.

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