Beyond Born–Oppenheimer theory for spectroscopic and scattering processes

Mukherjee, Bijit; Naskar, Koushik; Mukherjee, Soumya; Ghosh, Sandip; Sahoo, Tapas; Adhikari, Satrajit

doi:10.1080/0144235x.2019.1672987

Cited by 44 publications

(78 citation statements)

References 187 publications

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“…For about a century, the theory known as Born–Oppenheimer approximation (BOA) [18] has been used to solve the molecular Schrödinger equation. The success of the BOA depends primarily on the difference between the masses of the electrons and the nucleus, which makes it possible to separate the electron motion from the nuclear motion [19, 20]. In fact, electronic motion is parametrically dependent on the motion of nuclei.…”

Section: Introductionmentioning

confidence: 99%

“…In BOA, we can describe some of the chemical processes that mainly occur at lower energy regions of ground electronic state. In nature, a wide range of molecular phenomena (that involve electronically excited states such as photosynthesis, vision, charge transfer chemical reactions and solar energy conversion to photochemical reactions) occur beyond the BO approximation (BBO), when the coupling of electronic and nuclear motions leads to non‐adiabatic events [19, 20]. The forces governing the motion of the nucleus in a molecule are determined by adiabatic potential energy surfaces (PESs) and non‐adiabatic coupling terms (NACTs), which are the result of the BOA.…”

Section: Introductionmentioning

confidence: 99%

“…The forces governing the motion of the nucleus in a molecule are determined by adiabatic potential energy surfaces (PESs) and non‐adiabatic coupling terms (NACTs), which are the result of the BOA. Adiabatic PESs are derived from electronic Hamiltonian under the BOA, but NACTs combined momentum couplings between the motions of nuclei on two different adiabatic PESs [19]. Therefore, in order to understand the exact description of the molecular processes, a transition to beyond the BOA is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, in order to understand the exact description of the molecular processes, a transition to beyond the BOA is necessary. NACTs functions change sharply with nuclear coordinates and have singularity at conical intersections (CIs) of electronic states [19].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Dehestani

2021

Int J of Quantum Chemistry

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In F2O+ cation the first (2B2) and second excited (2A1) electronic states can be coupled with each other by anti‐symmetric stretching mode and thus conical intersection and non‐adiabatic dynamics play an important role in characterizing molecular properties. In this work, we tried to find a suitable computational method for determining equilibrium structures and harmonic vibrational frequencies of the three lowest electronic states of F2O+. To understand non‐adiabatic dynamics at conical intersections, we calculated the probability of electronic population on 2B2 and 2A1 excited electronic states using linear vibronic coupling Hamiltonian mode including all three vibrational modes (bending (ω1), symmetric stretching (ω2) and anti‐symmetric stretching (ω3)).The amount of vibronic coupling constant between these states is obtained 0.08 eV at multi reference configuration interaction/Aug‐cc‐pVQZ level of theory.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Dehestani

2021

Int J of Quantum Chemistry

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“…the grid-based MCTDH works with non-local PESs and couplings, it is necessary to remove the singular NAC by transforming the adiabatic or spin-diabatic electronic states to the diabatic representation(81)(82)(83). Vibronic coupling models are often used to…”

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confidence: 99%

Modeling Spin-Crossover Dynamics

Mukherjee

Fedorov

Varganov

2021

Annu. Rev. Phys. Chem.

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In this article, we review nonadiabatic molecular dynamics (NAMD) methods for modeling spin-crossover transitions. First, we discuss different representations of electronic states employed in the grid-based and direct NAMD simulations. The nature of interstate couplings in different representations is highlighted, with the main focus on nonadiabatic and spin-orbit couplings. Second, we describe three NAMD methods that have been used to simulate spin-crossover dynamics, including trajectory surface hopping, ab initio multiple spawning, and multiconfiguration time-dependent Hartree. Some aspects of employing different electronic structure methods to obtain information about potential energy surfaces and interstate couplings for NAMD simulations are also discussed. Third, representative applications of NAMD to spin crossovers in molecular systems of different sizes and complexities are highlighted. Finally, we pose several fundamental questions related to spin-dependent processes. These questions should be possible to address with future methodological developments in NAMD. Expected final online publication date for the Annual Review of Physical Chemistry, Volume 72 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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Construction of Beyond Born‐Oppenheimer Based Diabatic Surfaces and Generation of Photoabsorption Spectra: The Touchstone Pyrazine (C₄N₂H₄)

et al. 2022

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We construct theoretically "exact" and numerically "accurate" Beyond Born-Oppenheimer (BBO) based diabatic potential energy surfaces (PESs) of pyrazine (C 4 N 2 H 4 ) molecule involving lowest four excited adiabatic PESs (S 1 to S 4 ) and nonadiabatic coupling terms (NACTs) among those surfaces as functions of nonadiabatically active normal modes (Q 1 , Q 6a , Q 9a and Q 10a ) to compute its photoabsorption (PA) spectra. Those adiabatic PESs are calculated using CASSCF as well as MRCI based methodologies, where NACTs are obtained from CP-MCSCF approach. Employing ab initio quantities (adiabatic PESs and NACTs), it is possible to depict the conical intersections (CIs) and develop matrices of diabatic PESs over six normal mode planes. Once single-valued, smooth, symmetric and continuous 2 × 2 and 4 × 4 diabatic surface matrices are in hand for the first time, such matrices are used to perform multi-state multi-mode nuclear dynamics with the aid of Time-Dependent Discrete Variable Representation (TDDVR) methodology initializing the product type wavefunction on 1 1 B 1u (S 1 ) and 1 1 B 2u (S 2 ) states to obtain the corresponding PA spectra. TDDVR calculated spectra for those states (S 1 and S 2 ) obtained from BBO based 2 × 2 and 4 × 4 diabatic surface matrices show good and better agreement with the experimental results, respectively. Both of these calculated results depict better peak progression over the existing profiles of Multi-Configuration Time-Dependent Hartree (MCTDH) dynamics over 2 × 2 Vibronic Coupling Model (VCM) Hamiltonian.

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Beyond Born–Oppenheimer theory for spectroscopic and scattering processes

Cited by 44 publications

References 187 publications

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Modeling Spin-Crossover Dynamics

Construction of Beyond Born‐Oppenheimer Based Diabatic Surfaces and Generation of Photoabsorption Spectra: The Touchstone Pyrazine (C₄N₂H₄)

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Beyond Born–Oppenheimer theory for spectroscopic and scattering processes

Cited by 44 publications

References 187 publications

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F2O+ cation within multi reference configuration interaction calculations

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F2O+ cation within multi reference configuration interaction calculations

Modeling Spin-Crossover Dynamics

Construction of Beyond Born‐Oppenheimer Based Diabatic Surfaces and Generation of Photoabsorption Spectra: The Touchstone Pyrazine (C4N2H4)

Contact Info

Product

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About

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Investigation of nonadiabatic coupling and diabatic electronic population dynamics on F₂O⁺ cation within multi reference configuration interaction calculations

Construction of Beyond Born‐Oppenheimer Based Diabatic Surfaces and Generation of Photoabsorption Spectra: The Touchstone Pyrazine (C₄N₂H₄)