A Theoretical Study of BF + OH and BO + HF Reactions

1995 ◽  
Vol 418 ◽  
Author(s):  
M. R. Soto
Keyword(s):  
Reaction Mechanism ◽  
Ab Initio ◽  
Theoretical Study ◽  
Zero Point ◽  
Vibrational Frequencies ◽  
Multiconfigurational Methods ◽  
Optimized Geometries

AbstractThe reactions of BF + OH and BO + HF are critical reactions in the reaction mechanism of fluorine-enriched boron combustion.1 In this study, ab initio multiconfigurational methods have been used to calculate energies, optimized geometries, harmonic vibrational frequencies and zero-point energies for reactants, products and intermediates of these reactions. Results for the following reactive pathways will be discussed:

scholarly journals A theoretical study on the interaction of dinitrogen with rhodium

1994 ◽  
Vol 72 (3) ◽  
pp. 519-522
Author(s):  
T.H. Fang ◽  
M.L. McKee ◽  
S. D. Worley
Keyword(s):  
Binding Energy ◽  
Specific Surface ◽  
Ab Initio ◽  
Theoretical Study ◽  
Vibrational Frequencies ◽  
Surface Species ◽  
Ftir Studies ◽  
Future Work

Ab initio theoretical computations have been performed for RhN2, Rh+N2, Rh(N2)2, and Rh+(N2)2 species. The computed vibrational frequencies and binding-energy trends are in qualitative accord with prior FTIR studies of N2 interacting with supported Rh films. Computations of the type described herein should be useful in aiding the assignment of observed infrared bands to specific surface species in future work.

An ab initio study of the structures, barriers for internal rotation, vibrational frequencies, and thermodynamic functions of the hydrochlorofluorocarbon CH3CF2Cl and the corresponding radical CH2CF2Cl

1994 ◽  
Vol 72 (3) ◽  
pp. 561-567 ◽  
Author(s):  
S.J. Paddison ◽  
Yonghua Chen ◽  
E. Tschukow-Roux
Keyword(s):  
Ab Initio ◽  
Internal Rotation ◽  
Vibrational Energy ◽  
Zero Point ◽  
Heat Of Formation ◽  
Vibrational Frequencies ◽  
Radical Center ◽  
Molecular Orbital Calculations ◽  
Parent Molecule ◽  
Moller Plesset

Ab initio molecular orbital calculations were performed using the GAUSSIAN 90 system of programs at the HF/6-31G* level of theory, on the hydrochlorofluorocarbon (HCFC) 1-chloro-1,1-difluoroethane and the 1-chloro-1,1-difluoroethyl radical. Equilibrium geometries, barriers for internal rotation, and harmonic vibrational frequencies were thus calculated. A single conformational minimum in the potential energy surface was located for both the radical and the parent molecule. The radical center in CH2CF2Cl was found to be nonplanar. Transition structures for internal rotation about the C—C bond were located for both the molecule and the radical using analytical methods. The rotation barriers, evaluated at the fourth-order Møller–Plesset perturbation theory ((U)MP4/6-311G**/6-31G*). were calculated after inclusion of zero-point vibrational energy differences to be 1.11 and 4.12 kcal/mol for the radical and the parent molecule, respectively. Computed thermodynamic properties including heat capacity, entropy, enthalpy, and free energy functions are reported as a function of temperature. Using an experimentally measured heat of formation of CH3CF2Cl at 298 K, the heat of formation of CH2CF2Cl was calculated to be −74.3 ± 1.7 kcal/mol. Tabulations of ΔH0f,T, ΔG0f,T, and log10Kf,T over the temperature range of 0–1500 K are also reported for both species.

Comparison of STO-3G and 3-21G ab initio harmonic force fields for ethane, propane, dimethyl ether, and cyclobutane: effects of geometry and scaling on calculated frequencies, eigenvectors, and infrared absorption intensities

1988 ◽  
Vol 66 (5) ◽  
pp. 1318-1332 ◽  
Author(s):  
R. Anthony Shaw ◽  
Charles Ursenbach ◽  
Arvi Rauk ◽  
Hal Wieser
Keyword(s):  
Force Field ◽  
Ab Initio ◽  
Dimethyl Ether ◽  
Infrared Absorption ◽  
Force Fields ◽  
Vibrational Frequencies ◽  
Harmonic Force ◽  
Scaling Factors ◽  
Bond Lengths ◽  
Optimized Geometries

Ab initio harmonic force fields were calculated for ethane, propane, dimethyl ether, and cyclobutane at the STO-3G and 3-21G levels. The calculated frequencies, displacement eigenvectors, and calculated infrared absorption intensities were compared as they derive from force constants that were (i) unsealed; (ii) scaled to fit observed vibrational frequencies reported in the literature; (iii) evaluated at the optimized geometries; and (iv) evaluated at structures for which the bond lengths were corrected from the optimized geometries according to published procedures. A total of nine combinations of ab initio force field/reference geometry/G-matrix geometry were investigated for each of the four molecules. The ability of scaling factors as the only variables to predict vibrational parameters from STO-3G and 3-21G force fields was explored. Conditions were examined for which the scaling factors are satisfactorily transferable among different molecules.

Theoretical study of the ketonization reaction mechanism of acetic acid over SiO2

2009 ◽  
Author(s):  
Mendel Fleisher ◽  
E. Lukevics ◽  
L. Leite ◽  
D. Jansone ◽  
K. Edolfa ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Theoretical Study
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