Experimental Studies of H13CO+ Recombining with Electrons at Energies between 2鈥?0鈥?00 meV

详细信息    查看全文

• 作者：Mathias Hamberg ; Iryna Kashperka ; Richard D. Thomas ; Evelyne Roueff ; Vitali Zhaunerchyk ; Mathias Danielsson ; Magnus af Ugglas ; Fabian 脰sterdahl ; Erik Vigren ; Magdalena Kaminska ; Anders K盲llberg ; Ansgar Simonsson ; Andras Paal ; Maryvonne Gerin ; Mats Larsson ; Wolf D. Geppert
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：August 7, 2014
• 年：2014
• 卷：118
• 期：31
• 页码：6034-6049
• 全文大小：521K
• ISSN：1520-5215

文摘

An investigation into the dissociative recombination process for H¹³CO⁺ using merged ion-electron beam methods has been performed at the heavy ion storage ring CRYRING, Stockholm, Sweden. We have measured the branching fractions of the different product channels at 0 eV collision energy to be the following: CO + H 87 卤 2%, OH + C 9 卤 2%, and O + CH 4 卤 2%. The formation of electronically excited CO in the dominant reaction channel has also been studied, and we report the following tentative branching fractions for the different CO product electronic states: CO(X ¹危⁺) + H, 54 卤 10%; CO(a ³螤) + H, 23 卤 4%; and CO(a鈥?³危⁺) + H, 23 卤 4%. The absolute cross section between 2鈥?0 000 meV was measured and showed resonance structures between 3 and 15 eV. The cross section was fitted in the energy range relevant to astrophysics, i.e., between 1 and 300 meV, and was found to follow the expression 蟽 = 1.3 卤 0.3 脳 10^鈥?6 E^{鈥?.29卤0.05} cm² and the corresponding thermal rate constant was determined to be k(T) = 2.0 卤 0.4 脳 10^鈥?(T/300)^{鈭?.79卤0.05} cm³ s^鈥?. Radioastronomical observations with the IRAM 30 m telescope of HCO⁺ toward the Red Rectangle yielded an upper column density limit of 4 脳 10¹¹ cm^鈥? of HCO⁺ at the 1蟽 level in that object, indicating that previous claims that the dissociative recombination of HCO⁺ plays an important role in the production of excited CO molecules emitting the observed Cameron bands in that object are not supported.