Vibrational energy levels for symmetric and asymmetric isotopomers of ammonia with an exact kinetic energy operator and new potential energy surfaces

2003 ◽  
Vol 118 (14) ◽  
pp. 6358-6369 ◽  
Author(s):  
Timo Rajamäki ◽  
Andrea Miani ◽  
Lauri Halonen
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Energy Operator ◽  
Kinetic Energy Operator ◽  
Vibrational Energy Levels ◽  
Energy Surfaces

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+.

Potential energy curves, spectroscopic constants, and vibrational energy levels of CS+(X2Σ+/A2Π)

2019 ◽  
Vol 118 (2) ◽  
pp. e1597199
Author(s):  
Lulu Zhang ◽  
Daguang Yue ◽  
Juan Zhao ◽  
Yuzhi Song ◽  
Qingtian Meng
Keyword(s):  
Potential Energy ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Potential Energy Curves ◽  
Spectroscopic Constants ◽  
Vibrational Energy Levels

scholarly journals Physics-Guided Curve Fitting for Potential-Energy Functions of Diatomic Molecules

2021 ◽  
Author(s):  
Karl Irikura
Keyword(s):  
Potential Energy ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Spectroscopic Constants ◽  
Energy Curve ◽  
Simple Strategy ◽  
Level Data ◽  
Vibrational Energy Levels ◽  
High Level ◽  
Fitted Function

When computing the potential-energy curve of a diatomic molecule for predictive spectroscopy, high-level calculations are usually desired. The best calculations are expensive, so few points are usually available. The points are fitted to a continuous function, such as a polynomial. Ro-vibrational energy levels are then computed using the fitted function, and spectroscopic constants extracted. However, there may be problems with overfitting, with inadequate flexibility of the fitting function, or with dependence of results upon the choice of fitting function. More fundamentally, the fitting function is selected using aesthetics or convenience, instead of physics. Here we suggest using a lower-level, high-resolution ab initio potential as a guide. Instead of fitting the sparse, high-level data directly, the energy differences between the high-level points and the guiding potential are fitted. The results are improved even with an inexpensive guiding potential. This simple strategy involves little additional effort and can be recommended for routine use. It is similar to some interpolation strategies in the literature of polyatomic molecules. When the guiding potential extends beyond the high-level data, extrapolations are also improved.

scholarly journals Anab initiobased full-dimensional potential energy surface for OH + O2⇄ HO3and low-lying vibrational levels of HO3

2019 ◽  
Vol 21 (25) ◽  
pp. 13766-13775 ◽  
Author(s):  
Xixi Hu ◽  
Junxiang Zuo ◽  
Changjian Xie ◽  
Richard Dawes ◽  
Hua Guo ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Quantum Dynamics ◽  
Energy Surface ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Vibrational Levels ◽  
Vibrational Energy Levels

A full-dimensional potential energy surface for HO3, including the HO + O2dissociation asymptote, is developed and rigorous quantum dynamics calculations based on this PES have been carried out to compute the vibrational energy levels of HO3.

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