Diatomics-in-molecules potential energy surfaces of (HeH2)+: An extended basis set calculation

1983 ◽  
Vol 76 (2) ◽  
pp. 259-269 ◽  
Author(s):  
F. Schneider ◽  
L. Zülicke ◽  
R. Polák ◽  
J. Vojtík
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Basis Set ◽  
Energy Surfaces ◽  
Extended Basis

Potential Energy Surface Calculations of Alanine Dipeptide using BVWN Density Functional Approach and 6-311G Basis Set

2009 ◽  
Vol 1219 ◽  
Author(s):  
Jyoti Singh ◽  
Subhash Chandra Singh ◽  
Narsingh Bahadur Singh
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Density Functional ◽  
Basis Set ◽  
Reaction Coordinates ◽  
Conformational Properties ◽  
Energy Surfaces ◽  
Polypeptide Chains ◽  
Alanine Dipeptide

AbstractThis work is devoted to a study of the conformational properties of alanine dipeptide. We have studied potential energy surfaces of alanine dipeptide molecule using density functional theoretical approach with 6-311G basis set. For this purpose potential energies of this molecule are calculated as a function of Ramachandran angles φ and ψ, which are important factors for the characterizations of polypeptide chains. These degrees of freedoms φ and ψ are important for the characterization of protein folding systems. Stable conformations, energy barriers and reaction coordinates of this important dipeptide molecule are calculated. Energy required for the transition of one conformation into other are also discussed.

scholarly journals New ab Initio Potential Energy Surfaces for the Renner-Teller Coupled 11A′ and 11A′′ States of CH2

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Haitao Ma ◽  
Chunfang Zhang ◽  
Zhijun Zhang ◽  
Xiaojun Liu ◽  
Wensheng Bian
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Electronic States ◽  
Nonlinear Least Squares ◽  
Basis Set ◽  
Least Squares Fit ◽  
Three Body ◽  
Energy Surfaces

New ab initio potential energy surfaces (PESs) for the two lowest-lying singlet 11A′ and 11A′′ electronic states of CH2, coupled by the Renner-Teller (RT) effect and meant for the spectroscopic study, are presented. The surfaces are constructed using a dual-level strategy. The internally contracted multireference configuration interaction calculations with the Davidson correction, using the aug-cc-pVQZ basis set, are employed to obtain 3042 points at the lower level. The core and core-valence correlation effects are taken into account in the ab initio calculations with a modified optimized aug-cc-pCVQZ basis set for the higher-level points. The analytical representations of these PESs, with the inclusion of the nonadiabatic RT terms, are obtained by the nonlinear least-squares fit of the calculated points to three-body expansion. Quantum dynamical calculations are performed on these PESs, and the computed vibronic energy levels for the two singlet electronic states are in excellent agreement with experiment.

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