On the direct formation of HO2 radicals after 248 nm irradiation of benzene C6H6 in the presence of O2
We present in this work the direct observation of HO 2 radicals after irradiation of benzene C 6 H 6 at 248 nm in the presence of O 2 . HO 2 radicals have been unambiguously identified using the very selective and sensitive detection of continuous wave cavity ring-down spectroscopy (cw-CRDS) coupled...
Uloženo v:
| Vydáno v: | Applied physics. B, Lasers and optics Ročník 92; číslo 3; s. 379 - 385 |
|---|---|
| Hlavní autoři: | , , , |
| Médium: | Journal Article Konferenční příspěvek |
| Jazyk: | angličtina |
| Vydáno: |
Berlin/Heidelberg
Springer-Verlag
01.09.2008
Springer Springer Nature B.V Springer Verlag |
| Témata: | |
| ISSN: | 0946-2171, 1432-0649 |
| On-line přístup: | Získat plný text |
| Tagy: |
Přidat tag
Žádné tagy, Buďte první, kdo vytvoří štítek k tomuto záznamu!
|
| Shrnutí: | We present in this work the direct observation of HO
2
radicals after irradiation of benzene C
6
H
6
at 248 nm in the presence of O
2
. HO
2
radicals have been unambiguously identified using the very selective and sensitive detection of continuous wave cavity ring-down spectroscopy (cw-CRDS) coupled to a laser photolysis reactor. HO
2
radicals were detected in the first vibrational overtone of the OH stretch at 6638.20 cm
-1
, using a DFB diode laser. This reaction might be important because 248 nm photolysis of H
2
O
2
has often been used in the past for studying the OH
•
-initiated degradation of C
6
H
6
, often using a large excess of C
6
H
6
over H
2
O
2
. The possible importance of the title reaction with respect to these former laboratory studies has been quantified through comparison with HO
2
•
signals obtained from 248 nm photolysis of H
2
O
2
: one obtains under our conditions (excess O
2
and total pressure of 6.6 kPa helium) from the 248 nm irradiation of identical initial concentrations [C
6
H
6
]=[H
2
O
2
] the following relative initial radical concentrations: [HO
2
•
]=(0.28±0.05)×[OH
•
]. Experiments with various O
2
concentrations have revealed that the origin of the HO
2
radicals is not the reaction of H-atoms with O
2
, but must originate from the reaction of O
2
with excited C
6
H
6
*
. The quantum yield of C
6
H
6
*
formation has been deduced to ϕ=0.2±0.1. |
|---|---|
| Bibliografie: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 ObjectType-Article-2 ObjectType-Feature-1 content type line 23 |
| ISSN: | 0946-2171 1432-0649 |
| DOI: | 10.1007/s00340-008-3065-8 |