Cooper, Joseph C;
Holland, David MP;
Ingle, Rebecca A;
Bonanomi, Matteo;
Faccialà, Davide;
De Oliveira, Nelson;
Abid, Abdul R;
... Rolles, Daniel; + view all
(2024)
Valence shell electronically excited states of norbornadiene
and quadricyclane.
The Journal of Chemical Physics
, 160
, Article 064305. 10.1063/5.0187707.
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Abstract
The absolute photoabsorption cross sections of norbornadiene (NBD) and quadricyclane (QC), two isomers with chemical formula C₇H₈ that are attracting much interest for solar energy storage applications, have been measured from threshold up to 10.8 eV using the Fourier transform spectrometer at the SOLEIL synchrotron radiation facility. The absorption spectrum of NBD exhibits some sharp structure associated with transitions into Rydberg states, superimposed on several broad bands attributable to valence excitations. Sharp structure, although less pronounced, also appears in the absorption spectrum of QC. Assignments have been proposed for some of the absorption bands using calculated vertical transition energies and oscillator strengths for the electronically excited states of NBD and QC. Natural transition orbitals indicate that some of the electronically excited states in NBD have a mixed Rydberg/valence character, whereas the first ten excited singlet states in QC are all predominantly Rydberg in the vertical region. In NBD, a comparison between the vibrational structure observed in the experimental 1¹B₁–1¹A₁ (3sa₁ ← 5b₁) band and that predicted by Franck–Condon and Herzberg–Teller modeling has necessitated a revision of the band origin and of the vibrational assignments proposed previously. Similar comparisons have encouraged a revision of the adiabatic first ionization energy of NBD. Simulations of the vibrational structure due to excitation from the 5b2 orbital in QC into 3p and 3d Rydberg states have allowed tentative assignments to be proposed for the complex structure observed in the absorption bands between ∼5.4 and 7.0 eV.
| Type: | Article |
|---|---|
| Title: | Valence shell electronically excited states of norbornadiene and quadricyclane |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/5.0187707 |
| Publisher version: | https://doi.org/10.1063/5.0187707 |
| Language: | English |
| Additional information: | © 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Photoabsorption, Synchrotron radiation, Ions and properties, Isomerism, Absorption spectroscopy, Oscillator strengths, Organic compounds, Chemical compounds, Absorption band, Rydberg states |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10187435 |
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