Implications Concerning the Electronic States of Ethylene and Other Olefins from Magnetic Circular Dichroism Measurements of Tetramethylethylene

Snyder, Patricia; Hansen, R.G.; Rowe, Elizabeth

doi:10.1021/jp9607430

Cited by 14 publications

(19 citation statements)

References 30 publications

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“…The best of the present knowledge about these states probably comes from magnetic circular dichroism measurements, indicating that several electronically excited level are actually present in the 42 800 and 50 000 cm Ϫ1 energy range. 55 When turning back to the present work, we therefore expect that the 50 000 cm Ϫ1 energy of the 200 nm pump photon is sufficient to excite the valence state. As in the ethylene case it is coupled to one or several dark levels, Rydberg or Zwitterionic states, which may be probed in the tetramethylethylene case because of more favorable energetics for photoionization.…”

Section: Tetramethylethylene "23-dimethyl But-2-ene…mentioning

confidence: 73%

Prereactive evolution of monoalkenes excited in the 6 eV region

Mestdagh

Visticot

Elhanine

et al. 2000

The Journal of Chemical Physics

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Articles you may be interested inEffect of chemical substitutions on photo-switching properties of 3-hydroxy-picolinic acid studied by ab initio methods J. Chem. Phys. 140, 084301 (2014); 10.1063/1.4865815 On the origin of ultrafast nonradiative transitions in nitro-polycyclic aromatic hydrocarbons: Excited-state dynamics in 1-nitronaphthalene J. Chem. Phys. 131, 224518 (2009); 10.1063/1.3272536Mass-analyzed threshold ionization study of vinyl bromide cation in the first excited electronic state using vacuum-ultraviolet radiation generated by four-wave mixing in HgThe time evolution of the first excited states of ethylene, and alkyl substituted ethylenes, isomers with formula C 6 H 12 , has been studied by the femtosecond pump probe method, using mass spectrometric detection, in the region of 6 eV ͑200 nm͒. Two cyclic alkenes of the formula C 6 H 10 have also been studied. These systems exhibit a multi-exponential decay characterized by a very short time decay, ranging from 20 fs͑ethylene͒ to 100 fs ͑trans hex-2-ene͒ and a longer decay, in the picosecond range follows for most of the alkyl isomers. The short time evolution is characteristic of wave packet motion on a steep potential surface. The initial motion has been identified as the torsion about the CC double bond resulting from excitation of the valence state. The evolution of the valence excited state of excited state ethylene ͓first studied by the group of Radloff, Chem. Phys. Lett. 288, 2044 ͑1997͔͒ has been taken as a reference. The extremely rapid evolution, 20 fs, without any longer temporal component is explained by the disappearance of the wave packet from the Franck-Condon region into a conical intersection leading to the ground state surface by reference to the theoretical calculations of Ohmine ͓J. Chem. Phys. 83, 2348 ͑1985͔͒. This motion is essentially multidimensional to reach the funnel to the ground state; it combines the torsion about the CC double bond with a pyramidalization about one of the carbon atoms and/or H atom migration from one carbon to the other. Cyclic alkenes exhibit a similar behavior as ethylene with a single ultrashort decay that arises from this same mechanism. Also in the other substituted alkenes the short decay has been assigned to the wave packet motion away from the Franck-Condon region under the influence of the torsion about the double bond. The final longer decay could also be captured in the case of tetramethylethylene by a 800 nm probe as the internal conversion to the ground state via a funnel more difficult to reach. These measurements emphasize the role of conical intersections which could not be brought into evidence without time dependent methods.

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Section: Tetramethylethylene "23-dimethyl But-2-ene…mentioning

confidence: 73%

Prereactive evolution of monoalkenes excited in the 6 eV region

Mestdagh

Visticot

Elhanine

et al. 2000

The Journal of Chemical Physics

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“…With very few exceptions such as the MCD spectrum recorded for tetramethylethylene in the gas phase,53 most experimental MCD data are recorded in solution or in a protein environment. Solvent effects both on excitation energies and transition moments can be substantial54 and also so for MCD.…”

Section: Introductionmentioning

confidence: 99%

Ab initio calculation of magnetic circular dichroism

Kjærgaard

Coriani

Ruud

2012

WIREs Comput Mol Sci

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We discuss the ab initio calculation of all terms contributing to a magnetic circular dichroism (MCD) spectrum—i.e., A, B, and C terms—and give an overview of the most recent methods that have been introduced for calculating these different contributions. Among them, we highlight the use of the complex polarization propagator approach because it may give direct access to the A and B terms of MCD. We also briefly discuss how ab initio calculations for analyzing experimental MCD spectra can be used to gain insight into the electronic excited states of molecules. © 2012 John Wiley & Sons, Ltd. This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods

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“…In fact, Rydberg transitions often exhibit a significant signal and dominate the magnetic circular dichroism spectrum. 11,[57][58][59] The magnetic circular dichroism and absorption spectra of propylene were obtained to gather information about the electronic structure of simple olefins, particularly ethylene.…”

Section: Introductionmentioning

confidence: 99%

Ethylene. Experimental Evidence for New Assignments of Electronic Transitions in the π → π* Energy Region. Absorption and Magnetic Circular Dichroism Measurements with Synchrotron Radiation

2004

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An exploration of the vacuum ultraviolet magnetic circular dichroism and absorption spectra of propylene and a comparison to ethylene spectra provides new information on the electronic structure of ethylene. Ethylene has three electronic transitions in the energy region previously assigned as two. The presently proposed assignments for these transitions are π → 3s(1Ag → 1B3u), π → π*(1Ag → 1B1u), and π → 3p. The lowest energy transition that was previously assigned as the beginning of the π → π* is assigned as the π → 3s transition. The π → π* and π → 3p transitions are accidentally degenerate in ethylene. The electronic transition with sharp structure doublets which was previously assigned as π → 3s is assigned as one of the π → 3p [π → 3pσ (1Ag → 1B2g), π → 3p y (1Ag → 1B1g), or π → 3p x (1Ag → 1A1g)] vibronically allowed electronic transitions. A case is presented that it is the π → 3pσ (1Ag → 1B2g) and/or the π → 3p y (1Ag → 1B1g) electronic transitions that are responsible for the sharp structured doublets in ethylene.

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Implications Concerning the Electronic States of Ethylene and Other Olefins from Magnetic Circular Dichroism Measurements of Tetramethylethylene

Cited by 14 publications

References 30 publications

Prereactive evolution of monoalkenes excited in the 6 eV region

Prereactive evolution of monoalkenes excited in the 6 eV region

Ab initio calculation of magnetic circular dichroism

Ethylene. Experimental Evidence for New Assignments of Electronic Transitions in the π → π* Energy Region. Absorption and Magnetic Circular Dichroism Measurements with Synchrotron Radiation

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