Ab Initio Calculations of Vibrational Energy Levels and Transition Dipole Moments of CO2 Molecules

2008 ◽  
Author(s):  
Zhi Liang ◽  
Hai-Lung Tsai
Keyword(s):  
Ab Initio ◽  
Vibrational Energy ◽  
Molecular Spectroscopy ◽  
Dipole Moments ◽  
Energy Levels ◽  
Wave Functions ◽  
Molecular Vibration ◽  
Transition Dipole ◽  
Transition Dipole Moments ◽  
Vibrational Energy Levels

Ab initio MD simulation of laser-matter interactions is a hot area in the study of the mechanisms of photo-dissociation, photo-ionization and laser induced chemical reactions. The major problems in the study of laser-molecule interactions are to determine the energies and wave functions of molecular vibration states and the molecular transition dipole moments. An efficient method is presented to calculate the intramolecular potential energies and electrical dipole moments of CO2 molecules at the electronic ground state by solving the Kohn-Sham (KS) equation for a total of 101,992 nuclear configurations. The Projector-Augmented Wave (PAW) exchange-correlation potential functionals and Plane Wave (PW) basis functions were used in solving the KS equation. The calculated intra-molecular potential function was then included in the pure vibrational Schro¨dinger equation to determine the vibrational energy eigen values and eigen functions. The vibrational wave functions combined with the calculated dipole moment function were used to determine the transition dipole moments. The calculated results have a good agreement with experimental values. These results can be further used to determinations of molecular spectroscopy and laser absorption coefficients.

Long-range behavior of the transition dipole moments of heteronuclear dimers XY (X, Y = Li, Na, K, Rb) based on ab initio calculations

2018 ◽  
Vol 20 (3) ◽  
pp. 1889-1896 ◽  
Author(s):  
E. A. Bormotova ◽  
S. V. Kozlov ◽  
E. A. Pazyuk ◽  
A. V. Stolyarov
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Excited States ◽  
Long Range ◽  
Internuclear Distance ◽  
Electronic Transition ◽  
Dipole Moments ◽  
Transition Dipole ◽  
Transition Dipole Moments

The electronic transition dipole moments between the ground and excited states converging to the lowest three dissociation limits of heteronuclear dimers XY (X, Y = Li, Na, K, Rb) were ab initio calculated and asymptotically analyzed at large internuclear distance.

Ab Initio Calculations of Infrared Absorption Cross Sections of CO2 Gas

2008 ◽  
Author(s):  
Zhi Liang ◽  
Hai-Lung Tsai
Keyword(s):  
Ab Initio ◽  
Cross Sections ◽  
Infrared Absorption ◽  
High Pressures ◽  
Vibrational Energy ◽  
Dipole Moments ◽  
Golden Rule ◽  
Absorption Cross ◽  
Transition Dipole ◽  
Co2 Gas

An ab initio model is used to determine the infrared absorption cross sections of CO2 gas as a function of laser wavelength. The intra-molecular potential energy and electric dipole moment of the CO2 molecule as a function of molecular nuclear configurations are obtained by solving the Kohn-Sham (KS) equation. The rotational constants at different vibrational levels, the vibrational energy eigen values and transition dipole moments are determined by solving the pure vibrational Schro¨dinger equation. Using the Fermi’s Golden Rule and all the calculated ab initio results, the absorption cross sections of CO2 gas at room temperature and one atmosphere pressure are obtained. The calculated results have a good agreement with experimental results. Based on the calculated ab initio results, the infrared absorption cross sections of CO2 gas at higher pressures are calculated. The absorption spectra at high pressures are found to be much smoother due to the overlaps between neighboring absorption line shapes.

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+.

scholarly journals Empirical Line Lists in the ExoMol Database

Atoms ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Yixin Wang ◽  
Jonathan Tennyson ◽  
Sergei Yurchenko
Keyword(s):  
Ab Initio ◽  
Diatomic Molecules ◽  
Dipole Moments ◽  
Molecular Line ◽  
Transition Dipole ◽  
Hamiltonian Models ◽  
Transition Dipole Moments ◽  
Line Positions

The ExoMol database aims to provide comprehensive molecular line lists for exoplanetary and other hot atmospheres. The data are expanded by inclusion of empirically derived line lists taken from the literature for a series of diatomic molecules, namely CH, NH, OH, AlCl, AlF, OH + , CaF, MgF, KF, NaF, LiCl, LiF, MgH, TiH, CrH, FeH, C 2 , CP, CN, CaH, and triplet N 2 . Generally, these line lists are constructed from measured spectra using a combination of effective rotational Hamiltonian models for the line positions and ab initio (transition) dipole moments to provide intensities. This work results in the inclusion of 22 new molecules (36 new isotopologues) in the ExoMol database.

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