Exploring covalently bonded diamondoid particles with valence photoelectron spectroscopy

Zimmermann, T.; Richter, R.; Knecht, A.; Fokin, Andrey A.; Koso, Tetyana V.; Chernish, Lesya V.; Gunchenko, Pavel A.; Schreiner, Peter R.; Möller, Thomas; Rander, Torbjörn

doi:10.1063/1.4818994

Cited by 28 publications

(34 citation statements)

References 34 publications

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“…We demonstrate that the interpretation of the PES of selected diamondoids 9 12 13 , for which the experimental data are available 14 15 , in terms of atomic-like, sharp electronic levels is bound to fail. As the geometries of these nano-objects are exactly known, they serve as testbeds to study the accuracy of the standard theoretical tools that aim at describing, from first principles, the electronic structure.…”

Section: Resultsmentioning

confidence: 97%

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

Gali¹,

Demján²,

Vörös³

et al. 2016

Nat Commun

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The development of theories and methods devoted to the accurate calculation of the electronic quasi-particle states and levels of molecules, clusters and solids is of prime importance to interpret the experimental data. These quantum systems are often modelled by using the Born–Oppenheimer approximation where the coupling between the electrons and vibrational modes is not fully taken into account, and the electrons are treated as pure quasi-particles. Here, we show that in small diamond cages, called diamondoids, the electron–vibration coupling leads to the breakdown of the electron quasi-particle picture. More importantly, we demonstrate that the strong electron–vibration coupling is essential to properly describe the overall lineshape of the experimental photoemission spectrum. This cannot be obtained by methods within Born–Oppenheimer approximation. Moreover, we deduce a link between the vibronic states found by our many-body perturbation theory approach and the well-known Jahn–Teller effect.

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Section: Resultsmentioning

confidence: 97%

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

Gali¹,

Demján²,

Vörös³

et al. 2016

Nat Commun

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“…[14] This contrasts with polyaromatic hydrocarbons (PAHs) that typically exhibit strong electronic transitions, which moreover fall at longer wavelengths, causing their interstellar IR emission bands to be ubiquitous and intense. [18][19] Laserand synchrotron-induced vibrationally resolved photoluminescence spectra of diamondoids isolated in the gas phase have also been reported. [14] Sparked by the astrophysical relevance, a large number of experimental and computational studies have been devoted to understanding the spectroscopic properties of neutral and ionized diamondoids in the gas phase.…”

Section: Introductionmentioning

confidence: 98%

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Bouwman

Horst

2018

ChemPhysChem

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A structural characterization of the products formed in the dissociative electron ionization of adamantane (C 10 H 16 ) is presented. Molecular structures of product ions are suggested based on multiple‐photon dissociation spectroscopy using the Free Electron Laser for Infrared eXperiments (FELIX) in combination with quantum‐chemical calculations. Product ions are individually isolated in an ion trap tandem mass spectrometer and their action IR spectra are recorded. Atomic hydrogen loss from adamantane yields the 1‐adamantyl isomer. The IR spectrum of the C 8 H 11 + product ion is best reproduced by computed spectra of 2‐ and 4‐protonated meta ‐xylene and ortho ‐ and para‐ protonated ethylbenzenes. The spectrum of the product ion at m/z 93 suggests that it is composed of a mixture of ortho ‐protonated toluene, para ‐protonated toluene and 1,2‐dihydrotropylium, while the spectrum of the m/z 79 ion is consistent with the benzenium ion. This study thus suggests that adamantane is efficiently converted into aromatic species and astrophysical implications for the interstellar medium are highlighted.

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“…2.3 Å). The experimental adiabatic ionization potential of 5а (7.47 eV) [30] is reproduced well with M06-2X, but not at B3LYP or MP2 (Table). As expected, the С=C bond length in 5a •+ increases relative to the neutral one, however, only little twisting is found at our levels of theory: 5а •+ remains nearly planar due to the effective β-hyperconjugation with participation of the С-С-bonds of adjacent cyclobutane fragments (the respective bond lengths increase from 1.56 Å in 5a to 1.63 Å in 5a •+ , Fig.…”

Section: Resultsmentioning

confidence: 88%

Noncovalent interactions in crowded olefinic radical cations

Fokin

Bahonsky

Koso

et al. 2020

J. org. pharm. chem.

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Noncovalent interactions in crowded olefinic radical cations Aim. To study the effect of electronic (α-and β-hyperconjugations) and steric (noncovalent interactions) factors on the structures of olefinic radical cations. Results and discussion. The effect of intramolecular dispersion interactions on the structures of crowded alkenes in the neutral and ionized forms has been studied at the density functional theory (DFT) level with and without dispersion corrections included, as well as at the MP2 theory level with medium size basis sets. The results obtained are compared to the available experimental data. An excellent agreement has been found between the experimental and MP2/DFT-computed geometries of sesquihomoadamantene, adamantylidene adamantane, bis-2,2,5,5-tetramethylcyclopentylidene, bis-D 3-homocub-4-ylidene, and bis-C S-homocub-8-ylidene in the neutral and ionized forms. The experimental ionization potentials are better reproduced with the DFT-methods. Experimental part. The structure and composition of compounds were proved by the methods of 1 H and 13 C NMR-spectroscopy, and GC-MS-analysis. Elemental analysis was performed for the compounds obtained. Conclusions. The twisting of the olefinic moieties in the sesquihomoadamantene and adamantylidene adamantane radical cations is determined by the balance between the σ-π-hyperconjugation and residual oneelectron π-bonding and is close to that of the prototypical ethylene radical cation (29°). The twisting reaches 55° for the bis-2,2,5,5-tetramethylcyclopentylidene radical cation due to substantial steric repulsions between methyl groups. At the same time, the ionized states of bis-D 3-homocub-4-ylidene and bis-C S-homocub-8-ylidene retain their planarity due to β-CC-hyperconjugation and intramolecular dispersion attractions.

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Exploring covalently bonded diamondoid particles with valence photoelectron spectroscopy

Cited by 28 publications

References 34 publications

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

Spectroscopic Characterization of the Product Ions Formed by Electron Ionization of Adamantane

Noncovalent interactions in crowded olefinic radical cations

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