Matrix effects on the absorption spectra of benzene trapped in rare gas matrices

Taleb, A.M.; Mohammed, Hassan H.

doi:10.1016/0301-0104(85)87047-6

Cited by 3 publications

(3 citation statements)

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“…In fact, taking the argon matrix as a reference, it can be seen that S 1 is red-shifted in the benzene and cyclohexane glasses by 0.18 and 0.10 eV, while T 1 is red-shifted by only 0.05 and 0.04 eV, respectively. , In a similar way, the low-lying electronic states in structurally relevant benzene are less perturbed by matrix than the high-lying states. The three absorption bands in benzene gas 1 A 1g → 1 E 1u (6.87 eV), 1 A 1g → 1 B 1u (6.10 eV), and 1 A 1g → 1 B 2u (4.79 eV) become red-shifted in solid argon by 0.15, 0.09, and 0.01 eV, respectively . Thus, the gap between T 1 and S 1 states of 0.76 eV in the argon matrix provides a lower bound to the gap in the jet-cooled aniline when two states are systematically shifted to lower energies.…”

Section: Resultsmentioning

confidence: 96%

“…The three absorption bands in benzene gas 1 A 1g → 1 E 1u (6.87 eV), 1 A 1g → 1 B 1u (6.10 eV), and 1 A 1g → 1 B 2u (4.79 eV) become redshifted in solid argon by 0.15, 0.09, and 0.01 eV, respectively. 96 Thus, the gap between T 1 and S 1 states of 0.76 eV in the argon matrix provides a lower bound to the gap in the jet-cooled aniline when two states are systematically shifted to lower energies. The upper bound of 0.77 eV corresponds to the case where, in contrast to the red-shifted S 1 , the T 1 origin is not perturbed by the argon matrix.…”

Section: Resultsmentioning

confidence: 98%

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Role of Triplet States in the Photodynamics of Aniline

2021

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The dynamics of excited heteroaromatic molecules is a key to understanding the photoprotective properties of many biologically relevant chromophores that dissipate their excitation energy nonreactively and thereby prevent the detrimental effects of ultraviolet radiation. Despite their structural variability, most heteroaromatic compounds share a common feature of a repulsive 1 πσ* potential energy surface. This surface can lead to photoproducts, and it can also facilitate the population transfer back to the ground electronic state by means of a 1 πσ*/S 0 conical intersection. Here, we explore a hidden relaxation route involving the triplet electronic state of aniline, which has recently been discovered by means of time-selected photofragment translational spectroscopy [J. Chem. Phys. 2019, 151, 141101]. By using the recently available analytical gradients for multiconfiguration pair-density functional theory, it is now possible to locate the minimum energy crossing points between states of different spin and therefore compute the intersystem crossing rates with a multireference method, rather than with the less reliable single-reference methods. Using such calculations, we demonstrate that the population loss of aniline in the T 1 ( 3 ππ * ) state is dominated by C 6 H 5 NH 2 →C 6 H 5 NH⸱ + H⸱ dissociation, and we explain the long nonradiative lifetimes of the T 1 ( 3 ππ * ) state at the excitation wavelengths of 294-264 nm.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 98%

Role of Triplet States in the Photodynamics of Aniline

2021

View full text Add to dashboard Cite

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“…The three absorption bands in benzene gas 1 A1g→ 1 E1u (6.87 eV), 1 A1g→ 1 B1u (6.10 eV), and 1 A1g→ 1 B2u (4.79 eV) become redshifted in solid argon by 0.15, 0.09, and 0.01 eV, respectively. 95 Thus, the gap between T1 and S1 states of 0.76 eV in the argon matrix provides a lower bound to the gap in the jet-cooled aniline when two states are systematically shifted to the lower energies. The upper bound of 0.77 eV corresponds to the case where, in contrast to the redshifted S1, the T1 origin is not perturbed by the argon matrix.…”

Section: Resultsmentioning

confidence: 99%

Role of Triplet States in the Photodynamics of Aniline

Lykhin

Truhlar²,

Gagliardi³

2021

Preprint

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The dynamics of excited heteroaromatic molecules is a key to understanding the photoprotective properties of many biologically relevant chromophores that dissipate their excitation energy nonreactively and thereby prevent the detrimental effects of ultraviolet radiation. Despite their structural variability, most heteroaromatic compounds share a common feature of a repulsive 1πσ* potential energy surface. This surface can lead to photoproducts, and it can also facilitate the population transfer back to the ground electronic state by means of a 1πσ*/S0 conical intersection. Here, we explore a hidden relaxation route involving the triplet electronic state of aniline, which has recently been discovered by means of time-selected photofragment translational spectroscopy [J. Chem. Phys. 2019, 151, 141101]. By using the recently available analytical gradients for multiconfiguration pair-density functional theory, it is now possible to locate the minimum energy crossing points between states of different spin and therefore compute the intersystem crossing rates with a multireference method, rather than with the less reliable single-reference methods. Using such calculations, we demonstrate that the population loss of aniline in the T1(3ππ*) state is dominated by C6H5NH2→C6H5NH⸱ + H⸱ dissociation, and we explain the long nonradiative lifetimes of the T1(3ππ*) state at the excitation wavelengths of 294‑264 nm.

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