Dynamics of intramolecular vibrational energy redistribution in deuteriated anthracenes: rotational band contour analysis and time-resolved measurements

Peng, Lawrence W.; Keelan, Brian; Semmes, D. H.; Zewail, Ahmed H.

doi:10.1021/j100330a040

Cited by 21 publications

(11 citation statements)

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“…The band positions and relative frequencies of sharp peaks are listed in Table . Most of low-frequency bands with frequencies 18−108 cm -1 may be due to intermolecular vibrational modes, since such low-frequency modes have not been observed in the spectrum of the anthracene monomer …”

Section: Resultsmentioning

confidence: 99%

Electronic Spectra of Jet-Cooled Anthracene Dimer: Evidence of Two Isomers in the Electronic Ground State

et al. 1998

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The broad and sharp absorption systems of anthracene in the 362-376 nm region have been confirmed to be due to dimeric species by measuring the resonantly enhanced two-photon ionization mass spectrum. The hole-burning spectrum indicated that two stable isomers exist in the S 0 state. The decay time of the excimer emission (300 ns) from the broad system is much longer than that of the emission from the sharp system ( 15( 5 ns), indicating that the electronic nature of the excited state is very different between the two systems. The difference in the excited-state potentials of the two systems has been discussed on the basis of the vibronic structures and the emission lifetimes.

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Section: Resultsmentioning

confidence: 99%

Electronic Spectra of Jet-Cooled Anthracene Dimer: Evidence of Two Isomers in the Electronic Ground State

et al. 1998

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“…In this work, we have shown that in closely-related species, point group symmetry does not appear to have a large effect on IVR, which is contrary to some other studies. 48,49,50 Two of these studies did not consider jet-cooled molecules, 48,50 and additionally in the ultrafast study 50 a 300 cm -1 wide pulse was used in creating the wavepacket, and hence in those experiments other factors are likely playing a role. In addition, two of the studies considered relatively high-lying levels, 49,50 where we would expect the DOS of states to be largely continuous.…”

Section: Discussionmentioning

confidence: 99%

“…We also note that a number of studies have tried to address the issue of the effect of symmetry on IVR. 48,49 For example, von Benten et al 50 studied benzene, benzene-d1 and the three constitutional isomers of difluorobenzene. They concluded that for both sets of molecules, lowering the symmetry led to an increase in the rate of IVR.…”

Section: Introductionmentioning

confidence: 99%

Effects of symmetry, methyl groups and serendipity on intramolecular vibrational energy dispersal

Tuttle

Gardner

Whalley

et al. 2019

Phys. Chem. Chem. Phys.

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We consider two key parameters that have been proposed to be important for vibrational energy delocalization, closely related to intramolecular vibrational redistribution (IVR), in molecules. These parameters are the symmetry of the molecule, and the presence of torsional (internal rotor) modes of a methyl group. We consider four para-disubstituted benzene molecules and examine their vibrational character. The molecules selected are para-difluorobenzene, para-chlorofluorobenzene, para-fluorotoluene, and para-xylene. This set of molecules allows the above parameters to be assessed in a systematic way. The probe we use is zero-electron-kinetic-energy (ZEKE) spectroscopy, which is employed in a resonant scheme, where the intermediate levels are selected vibrational levels of the S1 excited electronic state, with wavenumbers up to 1300 cm-1. We conclude that symmetry, and the presence of a methyl groups, do indeed have a profound effect on "restricted" IVR at low energies. This is underpinned by serendipitous coincidences in the energies of the levels, owing to small shifts in vibrational wavenumbers between molecules, so bringing levels into resonance. Additionally, methyl groups play an important role in opening up new routes for coupling between vibrations of different symmetry, and this is critical in the transition to "statistical" IVR at lower energies for molecules that contain them. Further, the presence of two methyl groups in the symmetrically-substituted p-xylene causes more widespread IVR than does the single methyl group in the asymmetrically-substituted p-fluorotoluene.

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“…In Figure 4, we show results on anthracene as a function of excess energy as an example of the different types of behavior where the time scales (> 18 ns to 22 ps) for the different regimes www.annualreviews.org/aronline Annual Reviews have been established; restricted IVR occurs between 700-1300 cm-1 and dissipative IVR is seen for energies greater than 1700 cm-~ in Sl. Other molecules in which the dynamics of IVR has been studied include stilbene (48), deuterated analogs of anthracene and stilbene (49,50), alkyl-substituted anthracenes (51), diphenyl-butadiene (52), pyrazine and deutero-pyrazine (53)(54)(55), isoquinoline (56,57), n-alkyl anilines (58), difluorobenzene (59), azulene (60), 1-methylindole (61), pyrimidine indole (63), tetrazene-Ar (see section on state-to-state microcanonical rates, below), perylene (64), naphthol (65), and fluorene (see section purely rotational coherence, below). In a few of these examples, the vibrational redistribution involves some interstate electronic coupling (pyrazine, pyrimidine, isoquinoline).…”

Section: Studiesmentioning

confidence: 99%

Ultrafast Molecular Reaction Dynamics in Real-Time: Progress Over a Decade

Khundkar¹,

Zewail²

1990

Annu. Rev. Phys. Chem.

317

123

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Dynamics of intramolecular vibrational energy redistribution in deuteriated anthracenes: rotational band contour analysis and time-resolved measurements

Cited by 21 publications

References 0 publications

Electronic Spectra of Jet-Cooled Anthracene Dimer: Evidence of Two Isomers in the Electronic Ground State

Electronic Spectra of Jet-Cooled Anthracene Dimer: Evidence of Two Isomers in the Electronic Ground State

Effects of symmetry, methyl groups and serendipity on intramolecular vibrational energy dispersal

Ultrafast Molecular Reaction Dynamics in Real-Time: Progress Over a Decade

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