A Theoretical Study on the Mechanism of the Superacid-Catalyzed Unimolecular Isomerization ofn-Alkanes andn-Alkenes. Comparison between ab Initio and Density Functional Results

1996 ◽  
Vol 100 (41) ◽  
pp. 16514-16521 ◽  
Author(s):  
M. Boronat ◽  
P. Viruela ◽  
A. Corma
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Results

THEORETICAL STUDY OF HYDROGEN BONDED CLUSTERS OF AMMONIA AND FULMINIC ACID

2008 ◽  
Vol 07 (02) ◽  
pp. 277-286 ◽  
Author(s):  
ABEDIEN ZABARDASTI ◽  
SAEID AMANI ◽  
MARYAM SALEHNASSAJ ◽  
ALI H. KIANFARD
Keyword(s):  
Ab Initio ◽  
Density Functional Calculations ◽  
Cluster Size ◽  
Density Functional ◽  
Theoretical Study ◽  
Cooperative Effect ◽  
Stabilization Energy ◽  
Topological Parameters ◽  
Hydrogen Bonded

Ab initio and density functional calculations are used to analyze the interaction between a molecule of fulminic acid with one, two, three, and four molecules of ammonia along with a 2:2 complex at B3LYP/6-311++G(d, p) and MP2/6-311++G(d, p) computational levels. Cooperative effect (CE) in terms of stabilization energy of clusters is calculated and discussed as well. For the studied clusters, the CE is increased with increasing cluster size. Red shifts of H – C stretching frequency for complexes involving HCNO as H -donor are predicted. Atom in molecules is used to analyze the cooperative effect on topological parameters.

Theoretical Study of the Mechanism of the Addition of Diazomethane to Ethylene and Formaldehyde. Comparison of Conventional ab Initio and Density Functional Methods

1998 ◽  
Vol 102 (49) ◽  
pp. 10106-10112 ◽  
Author(s):  
Vicenç Branchadell ◽  
Elena Muray ◽  
Antonio Oliva ◽  
Rosa M. Ortuño ◽  
Cristóbal Rodríguez-García
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Theoretical Study ◽  
Density Functional Methods ◽  
Functional Methods

A theoretical study of Si4H2 cluster with ab initio and density functional theory methods

2001 ◽  
Vol 114 (3) ◽  
pp. 1278-1285 ◽  
Author(s):  
Wen-Ning Wang ◽  
Hai-Rong Tang ◽  
Kang-Nian Fan ◽  
Suehiro Iwata
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory

Ab initio and DFT studies on the structures, binding energies and nature of bonds in X2Y3 metal clusters (X+ = Li+, Na+ and K+; ${\rm Y}_{3}^{2-} = {\rm Zn}_{3}^{2-}, {\rm Cd}_{3}^{2-}$ and ${\rm Hg}_{3}^{2-}$)

2015 ◽  
Vol 14 (06) ◽  
pp. 1550043 ◽  
Author(s):  
Masoud Hatami ◽  
Mehdi Bayat ◽  
Hassan Keypour ◽  
Sadegh Salehzadeh
Keyword(s):  
Ab Initio ◽  
Electrostatic Interactions ◽  
Density Functional ◽  
Theoretical Study ◽  
Population Analysis ◽  
Binding Energies ◽  
Energy Decomposition ◽  
Zinc Cadmium ◽  
Covalent Contribution ◽  
Wiberg Bond Indices

A comprehensive theoretical study on the structure and stability of linear and triangular isomers of anionic clusters of zinc, cadmium and mercury [Formula: see text] and their binding with one and two alkali metal cations ( X + = Li +, Na +, K +) has been investigated at the density functional (BP86 and B3LYP) and ab initio (MP2, MP4 and coupled cluster single and double (CCSD)) methods. The results showed that in all cases, the triangular geometry with D3h symmetry is more stable than linear one. The calculated values of interaction energies (IE) between [Formula: see text] anions and two X+ cations, Wiberg bond indices (WBI) and the electron densities at bond critical points (BCP), ρ(BCP), for Y–X bonds show that among all complexes investigated here at all levels of theory Zn 3 Li 2 and Hg 3 K 2 have the largest and the smallest values of IE, WBI and ρ(BCP), respectively. The natural charges of the atoms and WBI involved in the bonding as well as the global value of the charge transfer ΔQ from [Formula: see text] to X+ cation in X2Y3 clusters, evaluated through natural population analysis, confirmed that covalent contribution in Y–X bond formation increases from K + to Li +. Also the energy decomposition analyses (EDA) were used to detect the nature of interaction in the complexes. The results confirmed that the contribution of electrostatic interactions in present complexes is almost more than 70%.

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