Vapour phase carbonyl absorption in the far ultra-violet

Horwood, J. F.; Williams, JF

doi:10.1016/0371-1951(63)80245-3

“…[15] The S 2 state is due to an n!3s Rydberg excitation and occurs around 6.2 eV, above which follows the three 3p states at around 6.9 eV. [16,17] The Rydberg states of the cycloketones have also been extensively investigated using absorption, [13,14,16,[18][19][20] resonance-enhanced multiphoton ionization (REMPI), [17,[21][22][23] electron ionization [4] as well as TR-MS. [24][25][26][27] The three cycloketones represent a set of molecules with an increasing number of internal degrees of freedom (27, 36, and 45) as well as different point-group symmetries (C s , C 2 , and C s for cyclobutanone, cyclopentanone and cyclohexanone, respectively) incorporating the same chromophore. Certain specific differences between the molecules are present which could influence the time-scale of excited-state dynamics.…”

Section: Introductionmentioning

confidence: 99%

Coherent Motion Reveals Non‐Ergodic Nature of Internal Conversion between Excited States

Kuhlman

¹

,

Sølling

²

,

Møller

³

2012

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We found that specific nuclear motion along low-frequency modes is effective in coupling electronic states and that this motion prevail in some small molecules. Thus, in direct contradiction to what is expected based on the standard models, the internal conversion process can proceed faster for smaller molecules. Specifically, we focus on the S(2) →S(1) internal conversion in cyclobutanone, cyclopentanone, and cyclohexanone. By means of time-resolved mass spectrometry and photoelectron spectroscopy the relative rate of this transition is determined to be 13:2:1. Remarkably, we observe coherent nuclear motion on the S(2) surface in a ring-puckering mode and motion along this mode in combination with symmetry considerations allow for a consistent explanation of the observed relative time-scales not afforded by only considering the density of vibrational states or other aspects of the standard models.

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“…47 and 49. The → * absorption of gaseous acrolein exhibits a broad structureless band, 50 and the peaks of the absorption intensity were observed at 6.41, 51 6.42, 47 and 6.49 eV. 50 The strongest → * absorption of acrolein in aqueous solution was observed at 5.90 eV.…”

Section: Introductionmentioning

confidence: 99%

On the performance of quantum chemical methods to predict solvatochromic effects: The case of acrolein in aqueous solution

Aidas

¹

,

Møgelhøj

²

,

Nilsson

³

et al. 2008

The Journal of Chemical Physics

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The performance of the Hartree-Fock method and the three density functionals B3LYP, PBE0, and CAM-B3LYP is compared to results based on the coupled cluster singles and doubles model in predictions of the solvatochromic effects on the vertical n → * and → * electronic excitation energies of acrolein. All electronic structure methods employed the same solvent model, which is based on the combined quantum mechanics/molecular mechanics approach together with a dynamical averaging scheme. In addition to the predicted solvatochromic effects, we have also performed spectroscopic UV measurements of acrolein in vapor phase and aqueous solution. The gas-to-aqueous solution shift of the n → * excitation energy is well reproduced by using all density functional methods considered. However, the B3LYP and PBE0 functionals completely fail to describe the → * electronic transition in solution, whereas the recent CAM-B3LYP functional performs well also in this case. The → * excitation energy of acrolein in water solution is found to be very dependent on intermolecular induction and nonelectrostatic interactions. The computed excitation energies of acrolein in vacuum and solution compare well to experimental data.

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“…The → * absorption of gaseous acrolein exhibits a broad structureless band, 50 and the peaks of the absorption intensity were observed at 6.41, 51 6.42, 47 and 6.49 eV. 50 The strongest → * absorption of acrolein in aqueous solution was observed at 5.90 eV. 47 Based on the experimental data reported in Ref.…”

Section: Introductionmentioning

confidence: 92%

A subsystem density-functional theory approach for the quantum chemical treatment of proteins

Jacob

¹

,

Visscher

²

2008

The Journal of Chemical Physics

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The performance of the Hartree-Fock method and the three density functionals B3LYP, PBE0, and CAM-B3LYP is compared to results based on the coupled cluster singles and doubles model in predictions of the solvatochromic effects on the vertical n → * and → * electronic excitation energies of acrolein. All electronic structure methods employed the same solvent model, which is based on the combined quantum mechanics/molecular mechanics approach together with a dynamical averaging scheme. In addition to the predicted solvatochromic effects, we have also performed spectroscopic UV measurements of acrolein in vapor phase and aqueous solution. The gas-to-aqueous solution shift of the n → * excitation energy is well reproduced by using all density functional methods considered. However, the B3LYP and PBE0 functionals completely fail to describe the → * electronic transition in solution, whereas the recent CAM-B3LYP functional performs well also in this case. The → * excitation energy of acrolein in water solution is found to be very dependent on intermolecular induction and nonelectrostatic interactions. The computed excitation energies of acrolein in vacuum and solution compare well to experimental data.

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Vapour phase carbonyl absorption in the far ultra-violet

Cited by 12 publications

References 10 publications

Coherent Motion Reveals Non‐Ergodic Nature of Internal Conversion between Excited States

Coherent Motion Reveals Non‐Ergodic Nature of Internal Conversion between Excited States

On the performance of quantum chemical methods to predict solvatochromic effects: The case of acrolein in aqueous solution

A subsystem density-functional theory approach for the quantum chemical treatment of proteins

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