Time-resolved photoelectron imaging of excited state relaxation dynamics in phenol, catechol, resorcinol, and hydroquinone

Livingstone, Ruth A.; Thompson, Jason; Iljina, Marija; Donaldson, Ross J.; Sussman, Benjamin J.; Paterson, Martin J.; Townsend, David

doi:10.1063/1.4765104

Cited by 99 publications

(159 citation statements)

References 102 publications

Supporting

Mentioning

146

Contrasting

Order By: Relevance

“…46 We have also previously attributed the same process to dynamical observations in the excited state dynamics of phenol and the dihydroxybenzenes. 24 In the experiments under discussion here, we are in excess of 6000 cm −1 above the S 1 (ππ * ) origin in all cases, which is considerably higher than the experimentally determined IVR onset threshold in the excited 1 (ππ * ) states of similar aromatic systems such as hydroquinone (1650 cm −1 ) and anisole (940 cm −1 ). 47,48 The ultimate fate of the S 1 (ππ * ) state is not resolved in our measurements but several possibilities suggested on the basis of previous work in aniline include fluorescence, 49 intersystem crossing to lower-lying triplet states, 50 and internal conversion back to the S 0 ground state, where the role played by prefulvene-like structures has attracted some recent attention.…”

Section: A τ 2 and τ 3 Decay Associated Spectramentioning

confidence: 54%

“…24 Samples were introduced into the source chamber of a differentially pumped photoelectron spectrometer via an Even-Lavie pulsed molecular beam valve operating at 1 kHz. 25 Small strips of filter paper were soaked with sample and placed in a cartridge mounted within the valve body, directly behind the exit nozzle (150 µm diameter).…”

Section: B Preliminary One-color Photoelectron Spectramentioning

confidence: 99%

“…The left hand half of each image shows the result following application of our rapid matrix inversion approach. 24 Time-resolved photoelectron spectra were generated from the full set of image data recorded for each of the three molecules investigated. These plots are shown in Fig.…”

Section: Trpei Measurementsmentioning

confidence: 99%

See 2 more Smart Citations

Ultraviolet relaxation dynamics of aniline, N, N-dimethylaniline and 3,5-dimethylaniline at 250 nm

Thompson

Saalbach

Crane

et al. 2015

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Time-resolved photoelectron imaging was used to investigate the electronic relaxation dynamics of gas-phase aniline, N, N-dimethylaniline, and 3,5-dimethylaniline following ultraviolet excitation at 250 nm. Our analysis was supported by ab initio coupled-cluster calculations evaluating excited state energies and (in aniline) the evolution of a range of excited state physical properties as a function of N-H bond extension. Due to a lack of consistency between several earlier studies undertaken in aniline, the specific aim of this present work was to gain new insight into the previously proposed non-adiabatic coupling interaction between the two lowest lying singlet excited states S1(ππ(∗)) and S2(3s/πσ(∗)). The methyl-substituted systems N, N-dimethylaniline and 3,5-dimethylaniline were included in order to obtain more detailed dynamical information about the key internal molecular coordinates that drive the S1(ππ(∗))/S2(3s/πσ(∗)) coupling mechanism. Our findings suggest that in all three systems, both electronic states are directly populated during the initial excitation, with the S2(3s/πσ(∗)) state then potentially decaying via either direct dissociation along the N-X stretching coordinate (X = H or CH3) or internal conversion to the S1(ππ(∗)) state. In aniline and N, N-dimethylaniline, both pathways most likely compete in the depletion of S2(3s/πσ(∗)) state population. However, in 3,5-dimethylaniline, only the direct dissociation mechanism appears to be active. This is rationalized in terms of changes in the relative rates of the two decay pathways upon methylation of the aromatic ring system.

show abstract

Section: A τ 2 and τ 3 Decay Associated Spectramentioning

confidence: 54%

Section: B Preliminary One-color Photoelectron Spectramentioning

confidence: 99%

See 1 more Smart Citation

Ultraviolet relaxation dynamics of aniline, N, N-dimethylaniline and 3,5-dimethylaniline at 250 nm

Thompson

Saalbach

Crane

et al. 2015

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…As with several other reported spectrometer designs, [30][31][32][33][34][35][36] the ion optics assembly described in Ref. 25 provided a convenient starting point.…”

Section: A the New Ion Optics Assemblymentioning

confidence: 99%

Near ultraviolet photochemistry of 2-bromo- and 2-iodothiophene: Revealing photoinduced ring opening in the gas phase?

Marchetti

Karsili

Kelly

et al. 2015

The Journal of Chemical Physics

View full text Add to dashboard Cite

Velocity map imaging methods, with a new and improved ion optics design, have been used to explore the near ultraviolet photodissociation dynamics of gas phase 2-bromo- and 2-iodothiophene molecules. In both cases, the ground (X) and spin-orbit excited (X*) (where X = Br, I) atom products formed at the longest excitation wavelengths are found to recoil with fast, anisotropic velocity distributions, consistent with prompt C–X bond fission following excitation via a transition whose dipole moment is aligned parallel to the breaking bond. Upon tuning to shorter wavelengths, this fast component fades and is progressively replaced by a slower, isotropic recoil distribution. Complementary electronic structure calculations provide a plausible explanation for this switch in fragmentation behaviour—namely, the opening of a rival C–S bond extension pathway to a region of conical intersection with the ground state potential energy surface. The resulting ground state molecules are formed with more than sufficient internal energy to sample the configuration space associated with several parent isomers and to dissociate to yield X atom products in tandem with both cyclic and ring-opened partner fragments.

show abstract

“…Many other phenol analogues have also been studied in the gas-phase, [17][18][19][20][21] one of which is catechol (1,2-dihydroxybenzene) -a UV chromophore in a range of biomolecules, one of which is eumelanin. As one of three types of melanin, 22 eumelanin is largely responsible for skin's frontline defense to UV exposure.…”

Section: Introductionmentioning

confidence: 99%

Bridging the Gap between the Gas Phase and Solution Phase: Solvent Specific Photochemistry in 4-tert-Butylcatechol

et al. 2015

View full text Add to dashboard Cite

(2015) Bridging the gap between the gas and solution phase : solvent specific photochemistry in 4-tert-butylcatechol. Journal of Physical Chemistry A, 119 (50). pp. 11989-11996. Permanent WRAP URL:http://wrap.warwick.ac.uk/83205 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. Publisher's statement:This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry A, copyright © American Chemical Society after peer review and technical editing by the publisher.To access the final edited and published work see http://dx.doi.org/10.1021/acs.jpca.5b03621 A note on versions:The version presented here may differ from the published version or, version of record, if you wish to cite this item you are advised to consult the publisher's version. Please see the 'permanent WRAP url' above for details on accessing the published version and note that access may require a subscription. ABSTRACT: Eumelanin is a naturally synthesized ultraviolet light absorbing biomolecule, possessing both photoprotective and phototoxic properties. We infer insight into these properties of eumelanin using a bottom-up approach, by investigating a subunit analogue, 4-tert-butylcatechol. Utilizing a combination of femtosecond transient electronic absorption spectroscopy and time-resolved velocity map ion imaging, our results suggest an environmental-dependent relaxation pathway, following irradiation at 267 nm to populate the S1 ( 1 ππ*) state. Gas-phase and non-polar solution-phase measurements reveal that the S1 state decays through coupling onto the S2 ( 1 πσ*) state that is dissociative along the non-intramolecular hydrogen bonded 'free' O-H bond. This process is mediated by tunneling beneath an S1/S2 conical intersection and occurs in 4.9 ± 0.6 ps in the gas-phase and 27 ± 7 ps in the non-polar cyclohexane solution. Comparative studies on the deuterated isotopologue of 4-tert-butylcatechol in both the gas-and solution-phase (cyclohexane) reveals an average kinetic isotope effect of ~19 and ~7, respectively, supportive of O-H dissociation mediated by a quantum tunneling mechanism. In contrast, in the polar acetonitrile, the S1 state decays on a much longer timescale of 1.7 ± 0.1 ns. We propose that the S1 decay is now multicomponent, likely driven by internal c...

show abstract

Time-resolved photoelectron imaging of excited state relaxation dynamics in phenol, catechol, resorcinol, and hydroquinone

Cited by 99 publications

References 102 publications

Ultraviolet relaxation dynamics of aniline, N, N-dimethylaniline and 3,5-dimethylaniline at 250 nm

Ultraviolet relaxation dynamics of aniline, N, N-dimethylaniline and 3,5-dimethylaniline at 250 nm

Near ultraviolet photochemistry of 2-bromo- and 2-iodothiophene: Revealing photoinduced ring opening in the gas phase?

Bridging the Gap between the Gas Phase and Solution Phase: Solvent Specific Photochemistry in 4-tert-Butylcatechol

Contact Info

Product

Resources

About