Internal conversion in highly excited benzene and benzene dimer: femtosecond time-resolved photoelectron spectroscopy

Radloff, W.; Stert, V.; Freudenberg, Th.; Hertel, I. V.; Jouvet, Christophe; Dedonder‐Lardeux, C.; Solgadi, D.

doi:10.1016/s0009-2614(97)01142-1

Cited by 109 publications

(85 citation statements)

References 14 publications

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“…Similar to ethylene, while the standard semiempirical parameter sets yield unphysical dynamics, the genetic-algorithm reoptimized parameter sets yield results consistent with experiments and ab initio computations. For example, the newly optimized parameter sets predict an S2 lifetime of 100 fs, in agreement with experiment [21]. We have also conducted dynamics simulations using a limited set of most distinct and best non-dominated parameter sets for both ethylene and benzene, results of which are beyond the scope of this paper.…”

Section: Resultssupporting

confidence: 72%

Multiobjective genetic algorithms for multiscaling excited state direct dynamics in photochemistry

Sastry

Johnson

Thompson

et al. 2006

Proceedings of the 8th Annual Conference on Genetic and Evolutionary Computation

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This paper studies the effectiveness of multiobjective genetic and evolutionary algorithms in multiscaling excited state direct dynamics in photochemistry via rapid reparameterization of semiempirical methods. Using a very limited set of ab initio and experimental data, semiempirical parameters are reoptimized to provide globally accurate potential energy surfaces, thereby eliminating the need for fullfledged ab initio dynamics simulations, which are very expensive. Through reoptimization of the semiempirical methods, excited-state energetics are predicted accurately, while retaining accurate ground-state predictions. The results show that the multiobjective evolutionary algorithm consistently yields solutions that are significantly better-up to 230% lower error in the energy and 86.5% lower error in the energy-gradient-than those reported in the literature. Multiple high-quality parameter sets are obtained that are verified with quantum dynamical calculations, which show near-ideal behavior on critical and untested excited state geometries. The results demonstrate that the reparameterization strategy via evolutionary algorithms is a promising way to extend direct dynamics simulations of photochemistry to multi-picosecond time scales.

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Section: Resultssupporting

confidence: 72%

Multiobjective genetic algorithms for multiscaling excited state direct dynamics in photochemistry

Sastry

Johnson

Thompson

et al. 2006

Proceedings of the 8th Annual Conference on Genetic and Evolutionary Computation

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“…Qiu et al . also report observation of S 2 → T 3 ISC in benzene 67 while other studies assessing the S 2 deactivation of benzene do not report observations on the ISC pathway 65,66 …”

Section: Introductionmentioning

confidence: 98%

Distortion dependent intersystem crossing: A femtosecond time-resolved photoelectron spectroscopy study of benzene, toluene, and p-xylene

Stephansen¹,

Sølling²

2017

Structural Dynamics

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The competition between ultrafast intersystem crossing and internal conversion in benzene, toluene, and p-xylene is investigated with time-resolved photoelectron spectroscopy and quantum chemical calculations. By exciting to S2 out-of-plane symmetry breaking, distortions are activated at early times whereupon spin-forbidden intersystem crossing becomes (partly) allowed. Natural bond orbital analysis suggests that the pinnacle carbon atoms distorting from the aromatic plane change hybridization between the planar Franck-Condon geometry and the deformed (boat-shaped) S2 equilibrium geometry. The effect is observed to increase in the presence of methyl-groups on the pinnacle carbon-atoms, where largest extents of σ and π orbital-mixing are observed. This is fully consistent with the time-resolved spectroscopy data: Toluene and p-xylene show evidence for ultrafast triplet formation competing with internal conversion, while benzene appears to only decay via internal conversion within the singlet manifold. For toluene and p-xylene, internal conversion to S1 and intersystem crossing to T3 occur within the time-resolution of our instrument. The receiver triplet state (T3) is found to undergo internal conversion in the triplet manifold within ≈100–150 fs (toluene) or ≈180–200 fs (p-xylene) as demonstrated by matching rise and decay components of upper and lower triplet states. Overall, the effect of methylation is found to both increase the intersystem crossing probability and direct the molecular axis of the excited state dynamics.

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“…The phenol derivatives have been investigated as intensely as benzene [12,[15][16][17][18][19]. In the present work, we observe ultrafast dynamics of o-fluorophenol via the excited states studied with femtosecond TR-PEI.…”

Section: Introductionmentioning

confidence: 88%

“…Recent developments in the area of photoionization suggest that it may indeed be possible to use REMPI, combined with photoelectron spectroscopy (PES), to study ultrashort lived electronic states, provided ultrashort laser pulses are employed [9][10][11][12]. As a variant of femtosecond time-resolved photoelectron spectroscopy, femtosecond time-resolved photoelectron imaging (TR-PEI) is well suited to the study of ultrafast nonadiabatic processes [13,14].…”

Section: Introductionmentioning

confidence: 99%

Ultrafast dynamics of o-fluorophenol studied with femtosecond time-resolved photoelectron and photoion spectroscopy

Zheng

Qin

Long

et al. 2010

Sci. China Phys. Mech. Astron.

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The ultrafast dynamics of o-fluorophenol via the excited states has been studied by femtosecond time-resolved photoelectron imaging. The photoion and photoelectron spectra taken with a time delay between 267 nm pump laser and 800 nm probe laser provide a longer-lived S 1 electronic state of about ns timescale. In comparison, the spectra obtained by exciting the S 2 state with femtosecond laser pulses at 400 nm and ionizing with pulses at 800 nm suggest that the S 2 state has an ultrashort lifetime about 102 fs and reflects the internal conversion dynamics of the S 2 state to the S 1 state. o-fluorophenol, femtosecond time-resolved photoelectron imaging, excited states PACS: 06.60. Jn, 51.50.+v, 78.47.+p,

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Internal conversion in highly excited benzene and benzene dimer: femtosecond time-resolved photoelectron spectroscopy

Cited by 109 publications

References 14 publications

Multiobjective genetic algorithms for multiscaling excited state direct dynamics in photochemistry

Multiobjective genetic algorithms for multiscaling excited state direct dynamics in photochemistry

Distortion dependent intersystem crossing: A femtosecond time-resolved photoelectron spectroscopy study of benzene, toluene, and p-xylene

Ultrafast dynamics of o-fluorophenol studied with femtosecond time-resolved photoelectron and photoion spectroscopy

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