Theoretical study of dynamical properties on reaction path in molecular internal coordinates

1999 ◽  
Vol 42 (6) ◽  
pp. 605-611 ◽  
Author(s):  
Zonghe Li ◽  
Hong Xu ◽  
Xianzhong Xu ◽  
Xiaoyan Cao ◽  
Ruozhuang Liu
2013 ◽  
Vol 10 (3) ◽  
pp. 1071-1081
Author(s):  
Baghdad Science Journal

Density Functional Theory (DFT) calculations were carried out to study the thermal cracking for acenaphthylene molecule to estimate the bond energies for breaking C8b-C5a , C5a-C5 , C5-C4 , and C5-H5 bonds as well as the activation energies. It was found that for C8b-C5a , C5-C4 , and C5-H5 reactions it is often possible to identify one pathway for bond breakage through the singlet or triplet states. The atomic charges , dipole moment and nuclear – nuclear repulsion energy supported the breakage bond .Also, it was found that the activation energy value for C5-H5 bond breakage is lower than that required for C8b-C5a , C5a-C5 , C5-C4 bonds which refer to C5-H5 bond in acenaphthylene molecule are weaker than C8b-C5a , C5a-C5 , C5-C4 bonds .It is reasonable to presume that C5-H5 bonds are broken first when a acenaphthylene molecule is exposed to thermal cracking. It seems that the characteristic planarity for the polyaromatic hydrocarbons is an important factor to acquire the molecule structure of the required stability along the reaction path . The trends in the bond energies and the configuration structures are discussed .


1997 ◽  
Vol 75 (7) ◽  
pp. 996-1001 ◽  
Author(s):  
Zhi-Xiang Wang ◽  
Ming-Bao Huang. ◽  
Ruo-Zhuang Liu

The CH + CH4 reaction has been studied by means of ab initio molecular orbital calculations incorporating electron correlation with Møller–Plesset perturbation theory up to second and fourth orders with the 6-31G(d,p) and 6-311++G(2d,p) basis sets. An energetically feasible insertion reaction path has been found in the potential energy surface that confirms the experimental proposal for the mechanism of the CH + CH4 reaction. The feature of the mechanism for the CH + CH4 insertion reaction is found to be different from the feature of the mechanisms for the CH + NH3, CH + H2O, and CH + HF insertion reactions, but somewhat similar to that for the CH2 + CH4 insertion reaction. Energetic results for the CH + CH4 reactions are in agreement with experiment. Keywords: CH radical, methane, reaction mechanism.


2011 ◽  
Vol 406 (11) ◽  
pp. 2143-2147 ◽  
Author(s):  
Himadri R. Soni ◽  
Sanjay D. Gupta ◽  
Sanjeev K. Gupta ◽  
Prafulla K. Jha

Tetrahedron ◽  
2007 ◽  
Vol 63 (47) ◽  
pp. 11617-11621 ◽  
Author(s):  
Angeles Peña-Gallego ◽  
Jesús Rodríguez-Otero ◽  
Enrique M. Cabaleiro-Lago

1996 ◽  
Vol 104 (17) ◽  
pp. 6491-6496 ◽  
Author(s):  
Kiet A. Nguyen ◽  
Charles F. Jackels ◽  
Donald G. Truhlar

2013 ◽  
Vol 304 (10) ◽  
pp. H1337-H1351 ◽  
Author(s):  
Yasutaka Kurata ◽  
Ichiro Hisatome ◽  
Mamoru Tanida ◽  
Toshishige Shibamoto

To elucidate the effects of hyperpolarization-activated current If on robustness of sinoatrial node (SAN) pacemaking in connection with intracellular Na+ concentration ( Nai) changes, we theoretically investigated 1) the impacts of If on dynamical properties of SAN model cells during inhibition of L-type Ca2+ channel currents ( ICaL) or hyperpolarizing loads and 2) If-dependent changes in Nai and their effects on dynamical properties of model cells. Bifurcation analyses were performed for Nai-variable and Nai-fixed versions of mathematical models for rabbit SAN cells; equilibrium points (EPs), limit cycles (LCs), and their stability were determined as functions of model parameters. Increasing If conductance ( gf) shrank ICaL conductance ( gCaL) regions of unstable EPs and stable LCs (rhythmic firings) in the Nai-variable system but slightly broadened that of rhythmic firings at lower gf in the Nai-fixed system. In the Nai-variable system, increased gf yielded elevations in Nai at EPs and during spontaneous oscillations, which caused EP stabilization and shrinkage in the parameter regions of unstable EPs and rhythmic firings. As gf increased, parameter regions of unstable EPs and stable LCs determined for hyperpolarizing loads shrank in the Nai-variable system but were enlarged in the Nai-fixed system. These findings suggest that 1) If does not enhance but rather attenuates robustness of rabbit SAN cells via facilitating EP stabilization and LC destabilization even in physiological gf ranges; and 2) the enhancing effect of If on robustness of pacemaker activity, which could be observed at lower gf when Nai was fixed, is actually reversed by If-dependent changes in Nai.


RSC Advances ◽  
2017 ◽  
Vol 7 (15) ◽  
pp. 8800-8807 ◽  
Author(s):  
Lukasz Kazmierczak ◽  
Dorota Swiatla-Wojcik ◽  
Marian Wolszczak

The UB3LYP/cc-pVTZ computations using three solvent models and pulse radiolysis measurements show predominance of the direct reaction path via [H–ONN]‡ in aqueous solution.


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