Ab initio study of a Bi3+ impurity in Cs2NaYCl6 and Y2O3: Comparison of perturbative and variational electron correlation methods

2006 ◽  
Vol 125 (17) ◽  
pp. 174709 ◽  
Author(s):  
Florent Réal ◽  
Valérie Vallet ◽  
Jean-Pierre Flament ◽  
Joël Schamps
Keyword(s):  
Ab Initio ◽  
Electron Correlation ◽  
Ab Initio Study ◽  
Correlation Methods

scholarly journals An ab initio study on the insertion reactions of CH [X2II] with NH3, H2O, and HF

1996 ◽  
Vol 74 (6) ◽  
pp. 910-917 ◽  
Author(s):  
Zhi-Xiang Wang ◽  
Ruo-Zhuang Liu ◽  
Ming-Bao Huang ◽  
Zhonghua Yu
Keyword(s):  
Ab Initio ◽  
Electron Correlation ◽  
Lower Energy ◽  
Energy Surface ◽  
Molecular Orbital Calculations ◽  
Ab Initio Study ◽  
Insertion Reactions ◽  
Moller Plesset ◽  
Ch Radical ◽  
Water Hydrogen

The mechanisms of the reactions of CH (X2II) with NH3, H2O, and HF have been studied by means of ab initio molecular orbital calculations incorporating electron correlation with Møller–Plesset perturbation theory up to the second order. For each of the three CH reactions, the insertion path has been found in the potential energy surface; in the calculated insertion path there exists an intermediate complex prior to the transition state that has a lower energy than the reactants. Energetic results indicate that insertion paths are favourable channels for these CH reactions, which is in line with proposals based on kinetic experiments. Key words: CH radical, ammonia, water, hydrogen fluoride, reaction mechanism.

A local-MP2 approach to the ab initio study of electron correlation in crystals and to the simulation of vibrational spectra: the case of Ice XI

2009 ◽  
Vol 123 (3-4) ◽  
pp. 327-335 ◽  
Author(s):  
Cesare Pisani ◽  
Lorenzo Maschio ◽  
Silvia Casassa ◽  
Migen Halo ◽  
Alessandro Erba
Keyword(s):  
Ab Initio ◽  
Vibrational Spectra ◽  
Electron Correlation ◽  
Ab Initio Study

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.

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