An ab initio Study of the Fulminate Anion-Cyanate Anion Rearrangement: Possible Intermediacy of the Oxazirinyl Anion

1997 ◽  
Vol 50 (2) ◽  
pp. 169 ◽  
Author(s):  
Yu-San Cheung ◽  
Wai-Kee Li
Keyword(s):  
Ab Initio ◽  
Basis Set ◽  
Ab Initio Methods ◽  
Ab Initio Study ◽  
High Level

The rearrangement of the fulminate anion (CNO¯) to the cyanate anion (OCN¯) has been studied with high-level ab initio methods. Geometry optimizations have been carried out at HF, MPn (n = 2-4), QCISD, QUISD(T), BD and BD(T) levels using the 6-31+G(d) basis set. The highest level of theory for the calculation of relative energies is QCISD(T)/6-311+G(3df, 2p). Results show that the rearrangement proceeds via an oxazirinyl anion intermediate, which is separated by barriers of 52·8 and 18·4 kJ mol-1 from CNO¯ and OCN¯, respectively.

Ab initio study of the structure of the hydrogen maleate anion

1993 ◽  
Vol 71 (3) ◽  
pp. 303-306 ◽  
Author(s):  
Miguel A. Ríos ◽  
Jesús Rodríguez
Keyword(s):  
Hydrogen Bond ◽  
Proton Transfer ◽  
Ab Initio ◽  
Electron Correlation ◽  
Basis Set ◽  
Ab Initio Methods ◽  
Ab Initio Study ◽  
Barrier Heights ◽  
Minimum Potential ◽  
Complete Optimization

The hydrogen maleate ion was studied by ab initio methods with complete optimization at the 3-21G, 6-31G, 6-31G**, and 6-31+G(2d,1p) levels. To study the influence of electron correlation, MP2 calculations have been done for the 6-31G** geometry. All calculations at the HF level predicted an asymmetric hydrogen bond with a double minimum potential governing transfer between the two equivalent structures. Moreover, both asymmetry and proton transfer barrier increase systematically with the power of the basis set used, with calculated barrier heights of 0.12 (3-21G), 1.59 (6-31G), 1.64 (6-31G**), and 2.00 kcal/mol (6-31+G). Only the introduction of the electron correlation at the MP2 level seems to predict a single minimum potential.

scholarly journals Density Functional Theory and Complete Basis Set Ab Initio Computational Study of Five-, Six-, Seven- and Eight-hydrogen Coordinated Carbon Cations

1999 ◽  
Vol 23 (8) ◽  
pp. 502-503
Author(s):  
Branko S. Jursic
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Computational Study ◽  
Basis Set ◽  
Functional Theory ◽  
Complete Basis ◽  
Complete Basis Set ◽  
High Level

High level ab initio and density functional theory studies are performed on highly protonated methane species.

Heats of Formation of 1,3,5,7-Cyclooctatetraene and Bicyclo[4.2.0]octa-2,4,7-triene. A High-Level ab Initio Study

1998 ◽  
Vol 102 (26) ◽  
pp. 4949-4951 ◽  
Author(s):  
O. Castaño ◽  
R. Notario ◽  
R. Gomperts ◽  
J.-L. M. Abboud ◽  
R. Palmeiro ◽  
...  
Keyword(s):  
Ab Initio ◽  
Heats Of Formation ◽  
Ab Initio Study ◽  
High Level

scholarly journals Global accurate diabatic potential surfaces for the reaction H + Li2

RSC Advances ◽  
2020 ◽  
Vol 10 (64) ◽  
pp. 39226-39240
Author(s):  
Ruilin Yin ◽  
Nan Gao ◽  
Jing Cao ◽  
Yanchun Li ◽  
Dequan Wang ◽  
...  
Keyword(s):  
Ab Initio ◽  
Adiabatic Potential ◽  
Basis Set ◽  
Potential Surfaces ◽  
High Level

The adiabatic potential energies for the lowest three states of a Li2H system are calculated with a high level ab initio method (MCSCF/MRCI) with a large basis set.

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