Study of strong Σ–Π and spin–orbit vibronic coupling effects in linear triatomic molecules

Mishra, Sabyashachi; Domcke, Wolfgang; Poluyanov, Leonid V.

doi:10.1016/j.chemphys.2006.05.023

Cited by 13 publications

(10 citation statements)

References 42 publications

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“…[33][34][35][38][39][40] In particular, vibronic coupling between and states has been found in many triatomic molecules. Domcke and co-workers have specifically developed the theoretical frameworks for strong 2 -2 and spin-orbit vibronic couplings, 41 showing that both the 2 3/2 and 2 states can be bent in strong coupling cases, while the 2 1/2 state remains linear. This is exactly in agreement with the current observation in AuC 2 .…”

Section: Strong 2 + -2 and Spin-orbit Vibronic Couplingmentioning

confidence: 99%

Probing the electronic structure and Au–C chemical bonding in AuC2− and AuC2 using high-resolution photoelectron spectroscopy

León

Yang

Wang

2014

The Journal of Chemical Physics

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We report photoelectron spectroscopy (PES) and high-resolution PE imaging of AuC2(-) at a wide range of photon energies. The ground state of AuC2(-) is found to be linear (C∞v, (1)Σ(+)) with a …8π(4)4δ(4)17σ(2)9π(4)18σ(2) valence configuration. Detachments from all the five valence orbitals of the ground state of AuC2(-) are observed at 193 nm. High-resolution PE images are obtained in the energy range from 830 to 330 nm, revealing complicated vibronic structures from electron detachment of the 18σ, 9π, and 17σ orbitals. Detachment from the 18σ orbital results in the (2)Σ(+) ground state of neutral AuC2, which, however, is bent due to strong vibronic coupling with the nearby (2)Π state from detachment of a 9π electron. The (2)Σ(+)-(2)Π vibronic and spin-orbit coupling results in complicated vibronic structures for the (2)Σ(+) and (2)Π3/2 states with extensive bending excitations. The electron affinity of AuC2 is measured accurately to be 3.2192(7) eV with a ground state bending frequency of 195(6) cm(-1). The first excited state ((2)A') of AuC2, corresponding to the (2)Π3/2 state at the linear geometry, is only 0.0021 eV above the ground state ((2)A') and has a bending frequency of 207(6) cm(-1). The (2)Π1/2 state, 0.2291 eV above the ground state, is linear with little geometry change relative to the anion ground state. The detachment of the 17σ orbital also results in complicated vibronic structures, suggesting again a bent state due to possible vibronic coupling with the lower (2)Π state. The spectrum at 193 nm shows the presence of a minor species with less than 2% intensity relative to the ground state of AuC2(-). High-resolution data of the minor species reveal several vibrational progressions in the Au-C stretching mode, which are assigned to be from the metastable (3)Π2,1,0 spin-orbit excited states of AuC2(-) to the (2)Π3/2,1/2 spin-orbit states of neutral AuC2. The spin-orbit splittings of the (3)Π and (2)Π states are accurately measured at the linear geometry. The current study provides a wealth of electronic structure information about AuC2(-) and AuC2, which are ideal systems to investigate the strong Σ-Π and spin-orbit vibronic couplings.

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Section: Strong 2 + -2 and Spin-orbit Vibronic Couplingmentioning

confidence: 99%

Probing the electronic structure and Au–C chemical bonding in AuC2− and AuC2 using high-resolution photoelectron spectroscopy

León

Yang

Wang

2014

The Journal of Chemical Physics

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“…37. The degenerate bending vibrational mode of the linear molecule couples the two components of the degenerate 2 ⌸ state in second order ͓Renner-Teller ͑RT͒ coupling͔ as well as the 2 ⌺ state with the 2 ⌸ state in first order ͑⌺-⌸ coupling͒.…”

Section: Vibronic Hamiltonianmentioning

confidence: 99%

“…34 Their assignments have been recently confirmed by high-resolution experiments 35 and high-level ab initio calculations. 37 We have derived a 6 ϫ 6 Hamiltonian matrix in a diabatic spin-electronic basis, considering only the degenerate bending mode. 37 We have derived a 6 ϫ 6 Hamiltonian matrix in a diabatic spin-electronic basis, considering only the degenerate bending mode.…”

Section: Introductionmentioning

confidence: 99%

“…36 Very recently, we have analyzed the VC of 2 ⌸ and 2 ⌺ electronic states of quasi-linear molecules with the inclusion of SO coupling by employing the microscopic ͑Breit-Pauli͒ SO-coupling operator in the single-electron approximation. 37. It has been shown that there exist several novel ⌺-⌸ VC terms of SO origin, which are absent when the usual phenomenological form of the SO coupling operator is used instead of its microscopic form, see Ref.…”

Section: Introductionmentioning

confidence: 99%

“…It has been shown that there exist several novel ⌺-⌸ VC terms of SO origin, which are absent when the usual phenomenological form of the SO coupling operator is used instead of its microscopic form, see Ref. We have determined the VC parameters from accurate ab initio calculations which are then used in the earlier developed ⌺-⌸ SO-VC model 37 to calculate the vibronic struc-ture of the 2 ⌸-2 ⌺ photodetachment spectra of CCCl − and CCBr − . It has been demonstrated that the interplay of strong ⌺-⌸ VC and strong SO splitting of the ⌸ state can result in unexpectedly complex vibronic spectra.…”

Section: Introductionmentioning

confidence: 99%

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Calculation of the vibronic structure of the photodetachment spectra of CCCl− and CCBr−

Mishra

Vallet

Poluyanov

et al. 2006

The Journal of Chemical Physics

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The vibronic structure of the closely spaced and strongly coupled X 2Sigma+ and A 2Pi states in the photodetachment spectra of CCCl- and CCBr- has been calculated by considering Sigma-Pi vibronic coupling together with spin-orbit coupling. The stretching modes are treated within the so-called linear-vibronic-coupling model. The vibronic and spin-orbit parameters have been determined by accurate ab initio electronic-structure calculations. While the nonrelativistic vibronic-coupling parameters are of approximately equal strength in CCCl and CCBr, the vibronic-coupling parameters of spin-orbit origin are found to be larger in the latter. The calculated photodetachment spectra of both systems are shown to exhibit a complicated vibronic structure due to strong Sigma-Pi vibronic coupling. The spectral envelopes of the calculated photodetachment spectra exhibit a double-hump reminiscent of strongly coupled Exe Jahn-Teller systems.

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Spin–orbit coupling and intersystem crossing in molecules

Marian

2011

WIREs Comput Mol Sci

704

799

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Many light‐induced molecular processes involve a change in spin state and are formally forbidden in non‐relativistic quantum theory. To make them happen, spin–orbit coupling (SOC) has to be invoked. Intersystem crossing (ISC), the nonradiative transition between two electronic states of different multiplicity, plays a key role in photochemistry and photophysics with a broad range of applications including molecular photonics, biological photosensors, photodynamic therapy, and materials science. Quantum chemistry has become a valuable tool for gaining detailed insight into the mechanisms of ISC. After a short introduction highlighting the importance of ISC and a brief description of the relativistic origins of SOC, this article focusses on approximate SOC operators for practical use in molecular applications and reviews state‐of‐the‐art theoretical methods for evaluating ISC rates. Finally, a few sample applications are discussed that underline the necessity of studying the mechanisms of ISC processes beyond qualitative rules such as the El‐Sayed rules and the energy gap law. © 2011 John Wiley & Sons, Ltd. This article is categorized under: Structure and Mechanism > Molecular Structures

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Study of strong Σ–Π and spin–orbit vibronic coupling effects in linear triatomic molecules

Cited by 13 publications

References 42 publications

Probing the electronic structure and Au–C chemical bonding in AuC2− and AuC2 using high-resolution photoelectron spectroscopy

Probing the electronic structure and Au–C chemical bonding in AuC2− and AuC2 using high-resolution photoelectron spectroscopy

Calculation of the vibronic structure of the photodetachment spectra of CCCl− and CCBr−

Spin–orbit coupling and intersystem crossing in molecules

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