Accurate theoretical study on the ground and first-excited states of Na2: potential energy curves, spectroscopic parameters, and vibrational energy levels

2016 ◽  
Vol 94 (12) ◽  
pp. 1259-1264 ◽  
Author(s):  
Lu-Lu Zhang ◽  
Yu-Zhi Song ◽  
Shou-Bao Gao ◽  
Ji-Hua Xu ◽  
Yong Zhou ◽  
...  
Keyword(s):  
Potential Energy ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Potential Energy Curves ◽  
Basis Set ◽  
Spectroscopic Parameters ◽  
Complete Basis Set ◽  
Internuclear Distances ◽  
Centrifugal Distortion Constants ◽  
Vibrational Energy Levels

Potential energy curves (PECs) for the ground and first-excited electronic states of Na2 are obtained by fitting the ab initio energies calculated at the MRCI(Q)/aug-cc-pVXZ (X = T, Q, 5) level of theory, which are subsequently extrapolated to the complete basis set limit. The relativistic effect and core–valence correlation are also considered. The PECs are accurate at both short and long internuclear distances with the root-mean-squared deviations being 0.72 cm−1 for Na2 [Formula: see text] and 0.36 cm−1 for Na2 [Formula: see text]. Utilizing the obtained PECs, we calculate the spectroscopic parameters, vibrational energy levels, classical turning points, inertial rotation, and centrifugal distortion constants, which are in good agreement with other theoretical and experimental work.

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

Accurate calculations on 20 Λ–S states of the BP radical: potential energy curves, spectroscopic parameters, and electronic transition properties

2015 ◽  
Vol 93 (10) ◽  
pp. 1088-1095 ◽  
Author(s):  
Xinxin Wang ◽  
Deheng Shi ◽  
Jinfeng Sun
Keyword(s):  
Potential Energy ◽  
Dipole Moments ◽  
Potential Energy Curves ◽  
Basis Set ◽  
Weakly Bound ◽  
Transition Dipole ◽  
Spectroscopic Parameters ◽  
Complete Basis Set ◽  
Condon Factors ◽  
S States

The potential energy curves of 20 Λ–S states of BP yeilded from the first two dissociation limits B(2Pu) + P(4Su) and B(2Pu) + P(2Du) have been calculated by the internally contracted multireference configuration interaction approach with the Davidson correction. Especially the core–valence correlation and scalar relativistic corrections are included in the present work. Potential energy curves are also extrapolated to the complete basis set limit. According to the potential energy curves, the spectroscopic parameters are determined and compared with those available in the literature. The convergent behavior of the present calculations is discussed with respect to the basis set and level of theory. Of the 20 states, the 23∑– and 33∑– states have the avoided crossings, which are very weakly bound ones, the 21∑–, and the 13Δ and 23Δ states possess a double well. Subsequently, the transition dipole moments, Franck–Condon factors, and radiative times of the transitions 31Π–b1Π, 23Δ–X3Π, 23∑––A3∑–, 33∑––A3∑–, and 15∑––15Π are calculated.

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.

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+.

Non-relativistic eigensolutions of molecular and heavy quarkonia interacting potentials via the Nikiforov Uvarov method

2020 ◽  
Vol 98 (12) ◽  
pp. 1125-1132 ◽  
Author(s):  
Ekwevugbe Omugbe
Keyword(s):  
Vibrational Energy ◽  
Energy Levels ◽  
Rotational Constant ◽  
Special Cases ◽  
Radial Schrödinger Equation ◽  
Interacting Systems ◽  
Centrifugal Distortion Constants ◽  
Vibrational Energy Levels ◽  
The Masses ◽  
Uvarov Method

In this paper, the analytical eigensolutions of the radial Schrödinger equation are obtained using the Nikiforov Uvarov method. Special cases of the modeled potential were discussed. The energy eigenvalues expressions for both quarkonia and diatomic molecular interacting systems are obtained. Furthermore, the masses of the charmonium and bottomonium mesons were computed. The vibrational energy levels, inertia rotational constant, and first two centrifugal distortion constants of the Kratzer–Fues oscillator were obtained in closed form. The results obtained are in excellent agreement with the results in the literature.

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