Potential energy surfaces for water dynamics: Reaction coordinates, transition states, and normal mode analyses

1989 ◽  
Vol 91 (10) ◽  
pp. 6318-6327 ◽  
Author(s):  
Hideki Tanaka ◽  
Iwao Ohmine
Keyword(s):  
Potential Energy ◽  
Normal Mode ◽  
Potential Energy Surfaces ◽  
Transition States ◽  
Water Dynamics ◽  
Reaction Coordinates ◽  
Energy Surfaces

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.

Vibrationally Averaged Potential Energy Surfaces and Microwave Spectra for Isotopic Ne-CO2 Complexes

2014 ◽  
Vol 670-671 ◽  
pp. 235-239
Author(s):  
Rong Chen ◽  
Xiao Ling Luo
Keyword(s):  
Potential Energy ◽  
Normal Mode ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Chem Phys ◽  
Lanczos Algorithm ◽  
Potential Surfaces ◽  
Microwave Spectra ◽  
Stretching Vibration ◽  
Energy Surfaces

Averaged potential energy surfaces for isotopic Ne–CO2complexes (20Ne–18O13C16O,20Ne–17O12C16O and22Ne–17O12C16O) are presented. According to the latestab initiopotential of20Ne–12C16O2(R. Chen, H. Zhu, D. Q. Xie, J. Chem. Phys, 133, 2010, 104302,) which incorporates its dependence on theQ3normal mode for the antisymmetric stretching vibration of the CO2molecule, we obtain the averaged potentials for20Ne–18O13C16O,20Ne–17O12C16O and22Ne–17O12C16O complexes by integrating the potential energy surface overQ3normal mode. Each averaged potential surfaces are found to have a T-shaped global minimum and two equivalent linear local minima. The radial DVR/angular FBR method and the Lanczos algorithm are applied to calculate the rovibrational energy levels. Comparison with the available experimental values showed an overall excellent agreement for all spectroscopic parameters and the microwave spectra.

Finding transition states using reduced potential-energy surfaces

2001 ◽  
Vol 105 (6) ◽  
pp. 463-472 ◽  
Author(s):  
Josep Maria Bofill ◽  
Josep Maria Anglada
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Transition States ◽  
Energy Surfaces

REACTION MECHANISM OF THE CCN RADICAL WITH NITROGEN DIOXIDE

2007 ◽  
Vol 06 (04) ◽  
pp. 661-674 ◽  
Author(s):  
LIN JIN ◽  
YI-HONG DING ◽  
JIAN WANG
Keyword(s):  
Reaction Mechanism ◽  
Potential Energy ◽  
Nitrogen Dioxide ◽  
Reaction Mechanisms ◽  
Low Temperatures ◽  
Potential Energy Surfaces ◽  
Transition States ◽  
Energy Surfaces

The complex singlet and triplet potential energy surfaces (PESs) of the [ C 2 N 2 O 2] system are performed at the B3LYP and Gaussian-3//B3LYP levels in order to investigate the possibility of the carbyne radical CCN in removal of nitrogen dioxide. Thirty minimum isomers and 36 transition states are located. Starting from the very energy-rich reactant R CCN + NO 2, the terminal C -attack adduct NCCN ( O ) O (singlet at -48.6 and triplet at -48.1 kcal/mol) is first formed on both singlet and triplet PESs. Subsequently, the singlet NCCN ( O ) O takes an O -transfer to form the intermediate singlet cis- NCC ( O ) NO (-120.1), which can lead to the fragments NCCO + NO (-94.4) without barrier. The simpler evolution of the triplet NCCN ( O ) O is the direct N – O rupture to form the final fragmentation NCCNO + 3 O (-31.0). However, the lower lying products 3 NCNO + CO (-103.3) and NCNCO + 3 O (-86.5) are kinetically much less competitive. All the involved transition states for the generation of NCCO + NO and NCCNO + 3 O lie much lower than the reactants, and it indicates that this reaction can proceed effectively even at low temperatures. We expect that the reaction CCN + NO 2 can play a role in both combustion and interstellar processes. Comparison is made between the CCN + NO 2 and CH + NO 2 reaction mechanisms.

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