Theoretical Investigation on the Low-Lying States of LaP Molecule

Elkahwagy, Nagat; Ismail, A. I.; Maize, S. M. A.; Mahmoud, K. R.

doi:10.1088/0256-307x/35/10/103101

“…The oxygen molecule (O 2 ), which plays an important role in the photo-physical, photochemical, and atmospheric spectroscopy, has received considerable attention over several decades. [1][2][3][4][5][6][7] The accurate and detailed information about the electronic states of O 2 , i.e., X 3 Σ − g state and low-lying excited states, the potential energy curves (PECs), and transition properties, which are significant for knowing more about spectrum of many kinds of molecules, [8][9][10] are required to understand the mechanism of the chemical reactions including oxygen molecule [11][12][13][14][15][16][17] and to evaluate the abundance of oxygen element in the universe and atmosphere. [15,18,19] The experimental investigations were performed for the ground state and several low-lying electronic states [20][21][22] several decades ago.…”

Section: Introductionmentioning

confidence: 99%

Molecular opacities of low-lying states of oxygen molecule*

Liang

¹

,

Peng

²

,

Li

³

et al. 2020

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The X 3 Σ g − , A′3Δu, A 3 Σ u + , 13Πg, and B 3 Σ u − electronic states of oxygen molecule (O2) are calculated by the multi-configuration self-consisted filed (MRCI) + Q method with the scalar relativistic correction and core–valence correlation correction. The obtained spectroscopic constants of the low-lying bound states are in excellent agreement with measurements. Based on the accurately calculated structure parameters, the opacities of the oxygen molecule at the temperatures of 1000 K, 2000 K, 2500 K, and 5000 K under a pressure of 100 atm (1 atm = 1.01325 × 105 Pa) and the partition functions between 10 K and 104 K are obtained. It is found that with the increase of temperature, the opacities for transitions in a long wavelength range are enlarged because of the larger population on excited electronic states at the higher temperatures.

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“…Such a set of rare-earth ccECPs would open new possibilities to study the broader family of RMn 6 Sn 6 with significantly improved accuracy using many-body methods such as CCSD(T), CI, QMC, and also DFT with appropriate DFAs. In fact, the current progress in applying real-space QMC to f -element systems seems to be hindered by the unavailability of accurate enough rare-earth ECPs, as we were able to find only a few QMC studies in the literature [103][104][105][106]. Therefore, we hope this work will motivate new studies in this avenue.…”

Section: Discussionmentioning

confidence: 99%

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

Annaberdiyev¹,

Mitáš²,

Krogel³

et al. 2023

Preprint

0

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A member of the RMn6Sn6 rare-earth family materials, TbMn6Sn6, recently showed experimental signatures of the realization of a quantum-limit Chern magnet. Despite the promising experimental results, theoretical studies with accurate electron correlations which probe these observations have been lacking. In this work, we use quantum Monte Carlo (QMC) and density functional theory with Hubbard U (DFT+U ) calculations to examine the electronic structure of TbMn6Sn6. To do so, we optimize accurate, correlation-consistent pseudopotentials for Tb and Sn using coupled-cluster and configuration-interaction (CI) methods. We find that DFT+U and single-reference QMC calculations suffer from the same overestimation of the magnetic moments as meta-GGA and hybrid density functional approximations. Our findings point to the need for improved orbitals/wavefunctions for this class of materials, such as natural orbitals from CI, or for the inclusion of multi-reference effects that capture the static correlations for an accurate prediction of magnetic properties. The necessity for multi-reference treatment is motivated by extrapolating the dynamic correlations to the exact limit. DFT+U with Mn magnetic moments adjusted to experiment predict the Dirac crossing in bulk to be close to the Fermi level, within ∼ 120 meV, in agreement with the experiments. Our nonstoichiometric slab calculations show that the Dirac crossing approaches even closer to the Fermi level, suggesting the possible realization of Chern magnetism in this limit.

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The role of electron correlations in the electronic structure of putative Chern magnet TbMn6Sn6

Annaberdiyev,

Mandal,

Mitas

et al. 2023

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A member of the RMn6Sn6 rare-earth family materials, TbMn6Sn6, recently showed experimental signatures of the realization of a quantum-limit Chern magnet. In this work, we use quantum Monte Carlo (QMC) and density functional theory with Hubbard U (DFT + U) calculations to examine the electronic structure of TbMn6Sn6. To do so, we optimize accurate, correlation-consistent pseudopotentials for Tb and Sn using coupled-cluster and configuration–interaction (CI) methods. We find that DFT + U and single-reference QMC calculations suffer from the same overestimation of the magnetic moments as meta-GGA and hybrid density functional approximations. Our findings point to the need for improved orbitals/wavefunctions for this class of materials, such as natural orbitals from CI, or for the inclusion of multi-reference effects that capture the static correlations for an accurate prediction of magnetic properties. DFT + U with Mn magnetic moments adjusted to the experiment predict the Dirac crossing in bulk to be close to the Fermi level, within ~120 meV, in agreement with the experiments. Our non-stoichiometric slab calculations show that the Dirac crossing approaches even closer to the Fermi level, suggesting the possible realization of Chern magnetism in this limit.

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Theoretical Investigation on the Low-Lying States of LaP Molecule

Cited by 6 publications

References 50 publications

Molecular opacities of low-lying states of oxygen molecule*

Molecular opacities of low-lying states of oxygen molecule*

The role of electron correlations in the electronic structure of putative Chern magnet TbMn$_6$Sn$_6$ using correlated methods

The role of electron correlations in the electronic structure of putative Chern magnet TbMn6Sn6

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