Ab Initio Study of s-trans-1,3-Butadiene Using Various Levels of Basis Set and Electron Correlation: Force Constants and Exponentially Scaled Vibrational Frequencies

1995 ◽  
Vol 99 (7) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jin Yong Lee ◽  
Ohyeon Hahn ◽  
Sang Joo Lee ◽  
Hyuk Soon Choi ◽  
Hansu Shim ◽  
...  
Keyword(s):  
Ab Initio ◽  
Electron Correlation ◽  
Vibrational Frequencies ◽  
Force Constants ◽  
Basis Set ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document