Jet-cooled fluorescence excitation spectra and carbonyl wagging potential energy functions of several cyclic ketones in their S1(n, π*) electronic excited states

Zhang, J.; Chiang, Whe-Yi; Sagear, P.; Laane, Jaan

doi:10.1016/0009-2614(92)85996-n

Cited by 15 publications

(5 citation statements)

References 12 publications

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“…In the cycloketones the S 1 state derives from an n!p* promotion with an observed band maximum around 4.1-4.4 eV. [1][2][3][4] The S 1 state has been extensively investigated by fluorescence and fluorescence excitation, [5][6][7][8][9][10][11][12] absorption, [1,3,5,13,14] and time-resolved mass-spectrometry (TR-MS). [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.…”

Section: Introductionmentioning

confidence: 99%

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

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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Section: Introductionmentioning

confidence: 99%

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

2012

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“…Determination of matrix-induced shifts can be difficult for multiphonon bands. The situation is rather different from purely electronic bands, narrow lines, or spectral holes at low temperatures, [33][34][35] where the 0-0 origin recorded in a cold molecular beam [36][37][38] can serve as a reference. Shifts of broad vibronic contours are often calculated with respect to vapor spectra, supposing that vibronic coupling parameters are not modified by solvent.…”

Section: Introductionmentioning

confidence: 99%

Solvent Dependence of n−π* Absorption in Acetone

Renge

2009

J. Phys. Chem. A

111

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A barely resolved structure can cause considerable loss of precision when locating the maxima of broad spectra. The centers of band envelopes were determined for the acetone n-pi* absorption in vapor, pure liquid, and solutions at 293 K. A complementary method of "band-halving" is proposed for accurate measurement of solvent-induced displacements. Solvent shifts span from -280 cm(-1) in CCl(4) to 465 cm(-1) in acetonitrile, and further to 1785 cm(-1) in hydrogen-bonding water, being negligible in n-alkanes. In the latter case the dispersive and induction shift components almost cancel mutually. Unbiased values of absolute frequency shifts will provide a reference to quantum chemical calculations, in particular, in nonpolar and weakly polar solvents where much controversy exists. The dipole moment in the excited state (mu(e) = 1.81 +/- 0.2 D, Deltamu = -1.81 D) and polarizability change (Deltaalpha = 0.6 +/- 0.2 A(3)) were estimated. A solvent set where the Onsager model is apparently applicable was used for the determination of mu(e). Remarkably, the bandwidth at half-maximum (fwhm) decreases in liquids, including water (6270 cm(-1)), as compared to vapor (6680 cm(-1)).

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“…1 depicts a UV absorption spectrum of cyclohexanone taken in n-hexane that shows the broad and structureless absorption band of the 1 nπ * state with its maximum around λ = 286 nm. 34 The adiabatic excitation en-ergy has so far not been experimentally determined, but the respective values are well known for acetone (3.774 eV), 6 cyclobutanone (3.756 eV), 35 3-cyclopenten-1-one (3.749 eV), 35 and cyclopentanone (3.754 eV) 35 from fluorescence excitation spectra of the jet-cooled molecules. Since the absorption 34 and emission 36 spectra of these (cyclo-)ketones are all very similar, we assume the electronic origin of the 1 nπ * state in cyclohexanone to be at a similar energy at or close to 3.75 eV.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast Relaxation Dynamics of the S1 (nπ*) State and the 3p and 3d Rydberg States in Cyclohexanone by Femtosecond Photoelectron Imaging

Hüter¹,

Helle²,

Temps³

2019

Preprint

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<div>The radiationless decay dynamics of the S1 (nπ*) state and the 3p and 3d Rydberg states of cyclohexanone are investigated using femtosecond time-resolved time-of- flight mass spectrometry and photoelectron imaging spectroscopy. After two-photon excitation of the 3p and 3d states, an ultrafast population transfer to the 3s state is observed within < 120 fs. We ascribe this behavior to strong vibronic interactions of the excited Rydberg states with the <sup>1</sup>ππ* valence state that enable an ultrafast population transfer via an avoided crossing and the subsequent passage of a conical intersection between the respective electronic states. Eventually, the 3s state deactivates by internal conversion to the S<sub>1</sub> (nπ*) state, which in turn is found to be long-lived with a decay time of ~ 300 - 800 ps.</div>

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Jet-cooled fluorescence excitation spectra and carbonyl wagging potential energy functions of several cyclic ketones in their S1(n, π*) electronic excited states

Cited by 15 publications

References 12 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

Solvent Dependence of n−π* Absorption in Acetone

Ultrafast Relaxation Dynamics of the S1 (nπ*) State and the 3p and 3d Rydberg States in Cyclohexanone by Femtosecond Photoelectron Imaging

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