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Optical band gap analysis of soot and organic carbon in premixed ethylene flames: Comparison of in-situ and ex-situ absorption measurements

Russo, Carmela ; Apicella, Barbara ; Tregrossi, Antonio ; Ciajolo, Anna ; Le, Kim Cuong LU orcid ; Török, Sandra LU and Bengtsson, Per-Erik LU orcid (2019) In Carbon 158. p.89-96
Abstract
The similarity of in-situ and ex-situ absorption/extinction properties was found by comparing data sets obtained in premixed flat ethylene flames (C/O = 0.77); both ex-situ absorption measurements at CNR of Naples and in-situ laser extinction/absorption measurements at Lund University. The optical band gap analysis was performed as a method to separate/evaluate the contributions to the UV–Visible absorption from organic carbon and soot by selecting two spectral regions; above 685 nm where only soot is assumed to absorb radiation and below 685 nm, where both soot and organic carbons absorb. Optical band gap for soot was analyzed separately from organic carbon, obtaining their individual contribution to the spectral absorption from... (More)
The similarity of in-situ and ex-situ absorption/extinction properties was found by comparing data sets obtained in premixed flat ethylene flames (C/O = 0.77); both ex-situ absorption measurements at CNR of Naples and in-situ laser extinction/absorption measurements at Lund University. The optical band gap analysis was performed as a method to separate/evaluate the contributions to the UV–Visible absorption from organic carbon and soot by selecting two spectral regions; above 685 nm where only soot is assumed to absorb radiation and below 685 nm, where both soot and organic carbons absorb. Optical band gap for soot was analyzed separately from organic carbon, obtaining their individual contribution to the spectral absorption from inception, throughout the growth region up to soot aggregation. While the optical band gap of soot strongly decreased along the flame from 1 to 0.1 eV, the band gap for organic carbons remained constant at ∼1.7–1.8 eV. By using the relationship of the optical band gap with nanostructural parameters (layer length and aromatic rings number), the average molecular weight of organic carbon around 400 u resulted rather far away from the molecular weight of 1000–2000 mass units evaluated for incipient soot consistently with the view of PAH species sticking together for particle inception. (Less)
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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Optical band gap, Soot, In-situ, Ex-situ
in
Carbon
volume
158
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:85082867633
ISSN
0008-6223
DOI
10.1016/j.carbon.2019.11.087
language
English
LU publication?
yes
id
882f12e7-46fb-46f4-aff7-4606e3044255
date added to LUP
2019-11-27 09:49:09
date last changed
2022-04-18 19:01:44
@article{882f12e7-46fb-46f4-aff7-4606e3044255,
  abstract     = {{The similarity of in-situ and ex-situ absorption/extinction properties was found by comparing data sets obtained in premixed flat ethylene flames (C/O = 0.77); both ex-situ absorption measurements at CNR of Naples and in-situ laser extinction/absorption measurements at Lund University. The optical band gap analysis was performed as a method to separate/evaluate the contributions to the UV–Visible absorption from organic carbon and soot by selecting two spectral regions; above 685 nm where only soot is assumed to absorb radiation and below 685 nm, where both soot and organic carbons absorb. Optical band gap for soot was analyzed separately from organic carbon, obtaining their individual contribution to the spectral absorption from inception, throughout the growth region up to soot aggregation. While the optical band gap of soot strongly decreased along the flame from 1 to 0.1 eV, the band gap for organic carbons remained constant at ∼1.7–1.8 eV. By using the relationship of the optical band gap with nanostructural parameters (layer length and aromatic rings number), the average molecular weight of organic carbon around 400 u resulted rather far away from the molecular weight of 1000–2000 mass units evaluated for incipient soot consistently with the view of PAH species sticking together for particle inception.}},
  author       = {{Russo, Carmela and Apicella, Barbara and Tregrossi, Antonio and Ciajolo, Anna and Le, Kim Cuong and Török, Sandra and Bengtsson, Per-Erik}},
  issn         = {{0008-6223}},
  keywords     = {{Optical band gap; Soot; In-situ; Ex-situ}},
  language     = {{eng}},
  month        = {{11}},
  pages        = {{89--96}},
  publisher    = {{Elsevier}},
  series       = {{Carbon}},
  title        = {{Optical band gap analysis of soot and organic carbon in premixed ethylene flames: Comparison of in-situ and ex-situ absorption measurements}},
  url          = {{https://lup.lub.lu.se/search/files/100051972/Manuscript.docx}},
  doi          = {{10.1016/j.carbon.2019.11.087}},
  volume       = {{158}},
  year         = {{2019}},
}