Ultrafast dynamics through conical intersections and intramolecular vibrational energy redistribution in styrene

Nunn, A. D. G.; Minns, Russell S.; Spesyvtsev, Roman; Bearpark, Michael J.; Robb, Michael A.; Fielding, Helen H.

doi:10.1039/c0cp01723j

Cited by 24 publications

(17 citation statements)

References 41 publications

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“…The experimental setup has been described elsewhere. 19,20,[24][25][26] Briefly, aniline (Sigma-Aldrich, 499%) and d 7 -aniline (98%, Sigma-Aldrich) were introduced into the velocity map imaging spectrometer by passing 800 mbar helium carrier gas through the liquid samples and expanding through a 50 mm nozzle. After collimation by a 1 mm skimmer, the molecular beam was intersected by femtosecond pump (272-238 nm) and probe (300 nm) laser pulses generated by frequency upconverting the outputs of two optical parametric amplifiers pumped by a commercial amplified Ti:sapphire femtosecond laser system.…”

Section: Methodsmentioning

confidence: 99%

Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm

Kirkby

Sala

Balerdi

et al. 2015

Phys. Chem. Chem. Phys.

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Femtosecond time-resolved photoelectron spectroscopy experiments have been used to compare the electronic relaxation dynamics of aniline and d7-aniline following photoexcitation in the range 272-238 nm. Together with the results of recent theoretical investigations of the potential energy landscape [M. Sala, O. M. Kirkby, S. Guérin and H. H. Fielding, Phys. Chem. Chem. Phys., 2014, 16, 3122], these experiments allow us to resolve a number of unanswered questions surrounding the nonradiative relaxation mechanism. We find that tunnelling does not play a role in the electronic relaxation dynamics, which is surprising given that tunnelling plays an important role in the electronic relaxation of isoelectronic phenol and in pyrrole. We confirm the existence of two time constants associated with dynamics on the 1(1)πσ* surface that we attribute to relaxation through a conical intersection between the 1(1)πσ* and 1(1)ππ* states and motion on the 1(1)πσ* surface. We also present what we believe is the first report of an experimental signature of a 3-state conical intersection involving the 2(1)ππ*, 1(1)πσ* and 1(1)ππ* states.

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Section: Methodsmentioning

confidence: 99%

Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm

Kirkby

Sala

Balerdi

et al. 2015

Phys. Chem. Chem. Phys.

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“…26,27 Parallel to this view, more recently, non-adiabatic paths through conical intersections (CIs) have slowly become the common explanation for fast IC processes. [28][29][30][31][32][33][34][35] Polycyclopenta-dithiophene-benzothiadiazole (PCPDTBT) is one of the most promising materials of a new class of lowband-gap copolymers, consisting of an electron-rich (cyclopentadithiophene, CPDT) and an electron-poor (benzothiadiazole, BT) unit. 36 Its ideal energy gap value, e.g.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast internal conversion in a low band gap polymer for photovoltaics: experimental and theoretical study

Fazzi

Grancini

Maiuri

et al. 2012

Phys. Chem. Chem. Phys.

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Ultrafast dynamics upon photoexcitation in a low band gap polymer for photovoltaics is investigated both experimentally and theoretically. Our work sheds light on the excess energy relaxation processes occurring immediately after photon absorption and responsible for dissipation in the photovoltaic process of light harvesting and energy storage. A peculiar non-adiabatic decay path through a conical intersection (CI) between the higher excited state S(2) and the first singlet state S(1) is identified by ultrafast spectroscopy and theoretical calculations. Ultrafast twisting of the initially flat conformation in S(2) drives the system to the CI connecting the two potential energy surfaces, actually eliciting an internal conversion within 60 femtoseconds, followed by planarization along the adiabatic surface in S(1). Relaxed potential energy profiles (PEPs) of ground and lowest excited states along a dihedral coordinate, calculated within the time dependent density functional theory (TDDFT) approach, support the S(2)/S(1) CI mechanism. Furthermore a screening of the widely used hybrid and range separated exchange-correlation (XC) DFT functionals has been carried out finding different descriptions of S(2)/S(1) PEPs and good agreement between experimental data and long-range corrected DFT.

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“…optically) at 254 nm or via internal conversion following 240 nm excitation. 32 Somewhat surprisingly, the former scenario (with 0.6 eV of internal vibrational energy) was reported to give rise to a much shorter lifetime (4 ps) than the latter (19 ps, with 0.9 eV S1(ππ*) vibrational excitation). This was attributed to the very different molecular geometries required to access conical intersections connecting the S1(ππ*) state to S2(ππ*) and the S0 ground state (into which the S1(ππ*) population ultimately decays).…”

Section: Although the Generation Of Femtosecond Uv/vuv Pulses Using Rmentioning

confidence: 99%

Ultrafast Molecular Spectroscopy Using a Hollow-Core Photonic Crystal Fiber Light Source

Kotsina

Belli

Gao

et al. 2019

J. Phys. Chem. Lett.

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We demonstrate, for the first time, the application of rare-gas filled hollow-core photonic crystal fibres (HC-PCFs) as tuneable ultraviolet light sources in femtosecond pump-probe spectroscopy. The time-resolved photoelectron imaging technique reveals non-adiabatic dynamical processes operating on three distinct timescales in the styrene molecule following excitation over the 242-258 nm region. These include ultrafast (<100 fs) internal conversion between the S2(ππ*) and S1(ππ*) electronic states and subsequent intramolecular vibrational energy redistribution within S1(ππ*). Compact, cost-effective and highly efficient bench-top HC-PCF sources have huge potential to open up many exciting new avenues for ultrafast spectroscopy in the ultraviolet and vacuum ultraviolet spectral regions. We anticipate that our initial validation of this approach will generate important impetus in this area. a Corresponding author: d.townsend@hw.ac.uk

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Ultrafast dynamics through conical intersections and intramolecular vibrational energy redistribution in styrene

Cited by 24 publications

References 41 publications

Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm

Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm

Ultrafast internal conversion in a low band gap polymer for photovoltaics: experimental and theoretical study

Ultrafast Molecular Spectroscopy Using a Hollow-Core Photonic Crystal Fiber Light Source

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Ultrafast dynamics through conical intersections and intramolecular vibrational energy redistribution in styrene

Cited by 24 publications

References 41 publications

Comparing the electronic relaxation dynamics of aniline and d7-aniline following excitation at 272–238 nm

Comparing the electronic relaxation dynamics of aniline and d7-aniline following excitation at 272–238 nm

Ultrafast internal conversion in a low band gap polymer for photovoltaics: experimental and theoretical study

Ultrafast Molecular Spectroscopy Using a Hollow-Core Photonic Crystal Fiber Light Source

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Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm

Comparing the electronic relaxation dynamics of aniline and d₇-aniline following excitation at 272–238 nm