An investigation of the excited state dynamics of cyclohexadiene in a supersonic jet

Share, P. E.; Kompa, K. L.

doi:10.1016/0301-0104(89)87173-3

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…The low symmetry of the system allows the doubly excited configuration to mix and contribute to this state, unlike in CHD14 (the V 5 state). While no evidence of this state is seen in the gas phase spectra, a transition has been reported 41 near 6.3 eV in the liquid phase. As Rydberg transitions do not appear in solution, the most likely assignment for this transition is to a valence state.…”

Section: Theoretical Results and Discussionmentioning

confidence: 94%

“…Two ab initio studies of the excited states of CHD13 have been reported. One, a MRCI calculation by Share et al, placed the intense transition to the first valence 1 B state (at the ground state geometry) at much higher energies than the weak transition to the lowest valence excited 1 A state placed the B vertically excited state below the A state.…”

Section: Introductionmentioning

confidence: 99%

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Electronic Spectra of 1,4-Cyclohexadiene and 1,3-Cyclohexadiene: A Combined Experimental and Theoretical Investigation

Merchán¹,

Serrano‐Andrés²,

Slater³

et al. 1999

J. Phys. Chem. A

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The electronically excited states of the two isomers 1,3-and 1,4-cyclohexadiene are examined by means of multiconfigurational second-order perturbation (CASPT2) theory with extended ANO-type basis sets. The calculations comprise the lower valence excited states plus all singlet 3s, 3p, and 3d members of the Rydberg series converging to the first ionization limit for the 1,3 isomer and the two first limits for 1,4. Companion optical and resonantly enhanced multiphoton ionization spectroscopic measurements were made on the 1,3 isomer. The computed vertical excitation energies were found to be in agreement with the available experimental energies for both systems. New assignments are proposed on the basis of combined experimental and theoretical efforts.

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Section: Theoretical Results and Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Electronic Spectra of 1,4-Cyclohexadiene and 1,3-Cyclohexadiene: A Combined Experimental and Theoretical Investigation

Merchán¹,

Serrano‐Andrés²,

Slater³

et al. 1999

J. Phys. Chem. A

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“…89,90 Earlier studies erroneously predicted S 2 to be the bright B state. 91,92 This may have led to the hypothesis that a S 2 -S 1 transition is involved in the excited state decay of Pro. 28 For Pro, TDDFT and CC2 calculations predict the first excited state to be the bright (1B-like) state (Table 2).…”

Section: Resultsmentioning

confidence: 99%

Unravelling the details of vitamin D photosynthesis by non-adiabatic molecular dynamics simulations

Tapavicza

Meyer

Furche

2011

Phys. Chem. Chem. Phys.

174

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We investigate the photodynamics of vitamin D derivatives by a fully analytical implementation of the linear response time-dependent density functional theory surface hopping method (LR-TDDFT-SH). Our study elucidates the dynamics of the processes involved in vitamin D formation at the molecular level and with femtosecond resolution. We explain the major experimental findings and provide new insights that cannot directly be obtained from experiments: firstly, we investigate the dynamics of the photoinduced ring-opening of provitamin D (Pro) and cyclohexadiene (CHD) and the subsequent rotational isomerization. In agreement with recent experiments and CC2 calculations, only the bright S(1) state is involved in the ring-opening reaction. Our calculations confirm the experimentally reported 5 : 1 ratio between the excited state lifetimes of Pro and CHD. The longer lifetimes of Pro are attributed to steric constraints of the steroid skeleton and to temperature effects, both emerging directly from our simulations. For CHD and Pro, we present an explanation of the biexponential decay recently reported by Sension and coworkers [Tang et al., J. Phys. Chem., 2011, 134, 104503]: our calculations suggest that the fast and slow components arise from a reactive and an unreactive reaction pathway, respectively. Secondly, we assess the wavelength dependent photochemistry of previtamin D (Pre). Using replica exchange molecular dynamics we sample the Pre conformers present at thermal equilibrium. Based on this ensemble we explain the conformation dependent absorption and the essential features of Pre photochemistry. Consistent with the experiments, we find ring-closure to occur mostly after excitation of the cZc conformers and at lower energies, whereas Z/E isomerization of the central double bond preferably occurs after excitation at higher energies. For the isomerization we provide the first theoretical evidence of the proposed hula-twist mechanism. Our results show that LR-TDDFT-SH is a highly valuable tool for studying the photochemistry of moderately large systems, even though challenges remain in the vicinity of conical intersections.

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“…The peak probe beam intensity in the focal plane was about 2ϫ10 13 W cm Ϫ2 . Whereas with low-intensity ionization ͑i.e., at 267 nm͒ the mass spectra of CHD and HT are almost indistinguishable, 22 they show a rather different fragmentation pattern when ionized by an intense-laser field: HT produces a strong H ϩ signal, while CHD gives practically no hydrogen ion. The TOF-spectrum of the H ϩ signal has a characteristic doublet shape indicating that it is due to Coulomb explosion of a doubly charged parent ion.…”

mentioning

confidence: 94%

Femtosecond photochemical ring opening of 1,3-cyclohexadiene studied by time-resolved intense-field ionization

Trushin

Fuß

Schikarski

et al. 1997

The Journal of Chemical Physics

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We found that hydrogen ion formation due to multielectron dissociative ionization by an intense-laser field is much less efficient with 1,3-cyclohexadiene than with its isomer 1,3Z,5-hexatriene (Z-HT). Moreover by suppressing the ionization barrier an intense-laser field ejects electrons most efficiently from molecular states of low ionization potential. After pumping 1,3-cyclohexadiene at 267 nm to its 1B2 state we probe the system by intense-laser field ionization with delayed 800 nm pulses. Monitoring of the parent ion C6H8+, of the main fragment C6H7+ and of H+ allows us to follow the motion from the 1B2 surface to the dark 2A1 state and from there towards the 2A1/1A1 conical intersection to the ground-state surface of the product. The measured 1B2 and 2A1 lifetimes are 43±3 and 77±7 fs, respectively, and the primary photoproduct cZc-HT is produced within 200 fs.

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An investigation of the excited state dynamics of cyclohexadiene in a supersonic jet

Cited by 9 publications

References 24 publications

Electronic Spectra of 1,4-Cyclohexadiene and 1,3-Cyclohexadiene: A Combined Experimental and Theoretical Investigation

Electronic Spectra of 1,4-Cyclohexadiene and 1,3-Cyclohexadiene: A Combined Experimental and Theoretical Investigation

Unravelling the details of vitamin D photosynthesis by non-adiabatic molecular dynamics simulations

Femtosecond photochemical ring opening of 1,3-cyclohexadiene studied by time-resolved intense-field ionization

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