===== On the Detection of the Hydroperoxyl Radical, HO2, in the ISM =====

B. Parise, P. Bergman, and F. Du,\\
used the IRAM 30 m and the APEX 12 m radio telescopes for the\\
**[[https://doi.org/10.1051/0004-6361/201219379|Detection of the Hydroperoxyl Radical HO<sub>2</sub> toward //ρ// Ophiuchi A: Additional Constraints on the Water Chemical Network]]**\\
//Astron. Astrophys.// **541**, Art. No. L11 (2012).\\
The //J<sub>K<sub>a</sub>,K<sub>c</sub></sub>// = 2<sub>0,2</sub> – 1<sub>0,1</sub> and 4<sub>0,4</sub> – 3<sub>0,3</sub> around 130.35 and 260.67 GHz, respectively, were detected. Both transitions displayed fine structure splitting of about 200 MHz. In addition, H-hyperfine splitting was resolved for the lower quantum number transition.\\
The source is the same in which H<sub>2</sub>O<sub>2</sub> was detected and the tentative detection of O<sub>2</sub> was confirmed very recently. The column density of HO<sub>2</sub> is very similar to that of H<sub>2</sub>O<sub>2</sub>, in reasonable agreement with model calculations.\\



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Contributor(s): H. S. P. Müller; 05, 2012


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