Supporting information: Optical properties of saturated and unsaturated carbonyl defects in polyethylene
| Autor: | Roma, G., Bruneval, F., Martin-Samos, L. |
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| Přispěvatelé: | CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Materials Research Laboratory (MRL), University of California [Santa Barbara] (UCSB), University of California-University of California, University of California [Santa Barbara] (UC Santa Barbara), University of California (UC)-University of California (UC) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Journal of Physical Chemistry B Journal of Physical Chemistry B, American Chemical Society, 2018, 122, ⟨10.1021/acs.jpcb.7b12172⟩ Journal of Physical Chemistry B, 2018, 122, ⟨10.1021/acs.jpcb.7b12172⟩ |
| ISSN: | 1520-6106 1520-5207 |
| DOI: | 10.1021/acs.jpcb.7b12172⟩ |
| Popis: | International audience; Polyethylene (PE), one of the simplest and most used aliphatic polymers, is generally provided with a number of additives, in particular antioxidants, because of its tendency to get oxidized. Carbonyl defects, a product of the oxidation of PE, are occurring in various forms, in particular saturated ones, known as ketones, where a C=O double bond substitutes a CH$_2$ group, andvarious unsaturated ones, i.e., with further missing hydrogens. Many experimental investigations of the optical properties in the visible-UV range mainly attribute thephotoluminescence of PE to one specific kind of unsaturated carbonyls, following analogies to the emission spectra of similar small molecules. However, the reason why saturated carbonyls should not be optically detected is not clear. We investigated the optical properties of PE with and without carbonyl defects using perturbative GW and the Bethe-Salpeter equation in order to take intoaccount excitonic effects. We discuss the calculated excitonic states in comparison with experimental absorption-emission energies and the stability of both saturated and unsaturated carbonyl defects. We conclude that the unsaturated defects are indeed the best candidate for the luminescence ofoxidized PE, and the reason is mainly due to oscillator strengths. |
| Databáze: | OpenAIRE |
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