VIBRATIONALLY AVERAGED POTENTIAL ENERGY SURFACES AND PREDICTED INFRARED SPECTRA OF THE He–18O13C18O AND He–16O13C16O COMPLEXES

2008 ◽  
Vol 07 (04) ◽  
pp. 707-717 ◽  
Author(s):  
YALI CUI ◽  
HONG RAN ◽  
DAIQIAN XIE
Keyword(s):  
Potential Energy ◽  
Normal Mode ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Finite Basis ◽  
Lanczos Algorithm ◽  
Stretching Vibration ◽  
Representation Method ◽  
Energy Surfaces ◽  
Variable Representation

Vibrationally averaged potential energy surfaces for isotopic He–CO 2 complexes ( He –18 O 13 C 18 O and He –16 O 13 C 16 O ) are presented. Based on the latest ab initio potential of He –16 O 12 C 16 O (Ran H, Xie D, J Chem Phys128:124323, 2008.) including the Q3 normal mode for the v3 antisymmetric stretching vibration of the CO 2 molecule, the averaged potentials for both He –18 O 13 C 18 O and He –16 O 13 C 16 O are obtained by integrating the potential energy surfaces over the Q3 normal mode. The averaged potentials have T-shaped global minima and two equivalent linear local minima. The radial discrete variable representation/angular finite basis representation method and Lanczos algorithm are employed to calculate the related rovibrational energy levels. The calculated band origin shifts of He –18 O 13 C 18 O and He –16 O 13 C 16 O are 0.1066 and 0.0914 cm-1, respectively, which agree very well with the observed values of 0.1123 and 0.0929 cm-1. The calculated rovibrational transitions of He –18 O 13 C 18 O and He –16 O 13 C 16 O are also in very good agreement with the available experimental spectra.

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.

POTENTIAL ENERGY SURFACES AND MICROWAVE SPECTRA FOR 20Ne–13C16O2, 22Ne–12C16O2 and 22Ne–13C16O2 COMPLEXES

2012 ◽  
Vol 11 (06) ◽  
pp. 1175-1182 ◽  
Author(s):  
RONG CHEN ◽  
HUA ZHU
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Global Minimum ◽  
Energy Levels ◽  
Three Dimensional ◽  
Lanczos Algorithm ◽  
Potential Surfaces ◽  
Microwave Spectra ◽  
Stretching Vibration ◽  
Energy Surfaces

We report averaged potential energy surfaces for isotopic Ne–CO2 complexes (20 Ne –13 C 16 O 2, 22 Ne –12 C 16 O 2 and 22 Ne –13 C 16 O 2). According to the latest ab initio potential of 20 Ne –12 C 16 O 2 (Chen R, Jiao EQ, Zhu H, Xie DQ, J Chem Phys133:104302, 2010) including the Q3 normal mode for the υ3 antisymmetric stretching vibration of the CO2 molecule. We obtain the averaged potentials for 20 Ne –13 C 16 O 2, 22 Ne –12 C 16 O 2 and 22 Ne –13 C 16 O 2 by the integration of the three-dimensional potential over the Q3 coordinate. The 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 observed values showed an overall excellent agreement for all spectroscopic parameters and the microwave spectra.

scholarly journals Formation of Van Der Waals Complexes in Concerted Unimolecular Elimination Processes

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Faina Dubnikova ◽  
Assa Lifshitz
Keyword(s):  
Potential Energy ◽  
Transition State ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Van Der Waals ◽  
State Theory ◽  
Van Der Waals Interactions ◽  
Decomposition Products ◽  
Quantum Chemical Methods ◽  
Energy Surfaces

Potential energy surfaces for three unimolecular elimination reactions: , , and were calculated using a variety of quantum chemical methods. It was shown that, in all the three cases, the transition state in the first step of the reaction leads to the production of the complex intermediates based on van der Waals interactions. In addition to the fact that the three complexes appear as intermediates on the potential energy surfaces, which means that they are not free entities, the entropy values of the two elimination products are far above those of the complexes due to their additional Sackur-Tetrode entropy. Moreover, the three vibrational frequencies of the H2O group in the (CH3)3COH complex and the H–Cl and H–F stretch frequencies in CH3CF3 and CH3CH2CH2Cl are quite different (see the various tables). The energy levels of the complexes were found to be below those of the corresponding decomposition products. Rate constants for the elimination processes were calculated from the potential energy surfaces using transition-state theory and were compared to available experimental data.

Vibrational energies of H3+ and Li3+ based on the diatomics-in-molecules potentials

1986 ◽  
Vol 51 (10) ◽  
pp. 2057-2062 ◽  
Author(s):  
Jan Vojtík ◽  
Vladimír Špirko ◽  
Per Jensen
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Potential Energy Surfaces ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Vibrational Motion ◽  
Variational Calculations ◽  
Vibrational Energies ◽  
Vibrational Energy Levels ◽  
Energy Surfaces

The present publication reports variational calculations of the vibrational energy levels for H3+, D3+, 6Li3+, and 7Li3+, starting from potential energy surfaces generated by the DIM scheme. The vibrational energies obtained agree semiquantitatively with those based on the best ab initio potentials available. The results seem to indicate that an analogous approach might be useful in describing the vibrational motion of heavier alkali cluster cations A3+.

Reduced-dimensional surface hopping with offline–online computations

2021 ◽  
Author(s):  
Zachary Morrow ◽  
Hyuk-Yong Kwon ◽  
Carl Tim Kelley ◽  
Elena Jakubikova
Keyword(s):  
Molecular Dynamics ◽  
Potential Energy ◽  
Molecular Dynamics Simulations ◽  
Potential Energy Surfaces ◽  
Energy Levels ◽  
Surface Hopping ◽  
Dynamics Simulations ◽  
Energy Surfaces ◽  
Nuclear Geometry ◽  
Dimensional Surface

Molecular dynamics simulations often classically evolve the nuclear geometry on adiabatic potential energy surfaces (PESs), punctuated by random hops between energy levels in regions of strong coupling, in an algorithm...

Beyond Born-Oppenheimer Based Diabatic Surfaces of 1,3,5-C6H3F3+ to Generate the Photoelectron Spectra Using Time-Dependent Discrete Variable Representation Approach

2021 ◽  
Author(s):  
Soumya Mukherjee ◽  
Satyam Ravi ◽  
Joy Dutta ◽  
Subhankar Sardar ◽  
Satrajit Adhikari
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Photoelectron Spectra ◽  
Time Dependent ◽  
Two Dimensional ◽  
Discrete Variable ◽  
Discrete Variable Representation ◽  
Energy Surfaces ◽  
Variable Representation

In this article, Beyond Born-Oppenheimer (BBO) treatment is implemented to construct diabatic potential energy surfaces (PESs) of 1,3,5-C6H3F3+ over a series [eighteen (18)] of two-dimensional (2D) nuclear planes constituted with...

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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