arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1207.2673astro-ph.GA
收藏

ISM和暗分子云中PAH阴离子的电子附着率:与其化学性质的关系

Electron attachment rates for PAH anions in the ISM and dark molecular clouds: dependence on their chemical properties

F. Carelli, T. Grassi, F. A. Gianturco

摘要:

背景:利用多通道量子散射方法,研究了具有不同稠环数的多环芳烃分子(PAHs)在宽的电子温度范围内的自由电子吸附行为.相关的横截面的计算反过来被用来模拟相应的附着率为每个系统的研究,这些速率参数化作为温度的函数,使用一个常用的表达式在星际介质(ISM)中的两体过程。目的:这项工作的范围是使用第一性原理来建立多环芳烃的电子附着过程的效率的化学性质的影响。方法:量子多通道散射方法产生的相关截面,因此的附件率,使用积分弹性截面计算在一个广泛的范围内的相关能量,从阈值高达1000 K和连接的附件,以低能量共振碰撞。研究结果:本分子获得的速率被发现显着变化的测试合奏本工作,并低于早期的值用于整个类的多环芳烃阴离子,当他们在ISM环境中的演变建模。这种差异的化学网络,包括多环芳烃和多环芳烃-物种的演变的影响进行了详细分析,并与以前的计算。

英文摘要:

CONTEXT: The attachment of free electrons to polycondensed aromatic ring molecules (PAHs) is studied for the variety of these molecules with different numbers of condensed rings and over a broad range of electron temperatures, using a multichannel quantum scattering approach. The calculations of the relevant cross sections are used in turn to model the corresponding attachment rates for each of the systems under study, and these rates are parametrized as a function of temperature using a commonly employed expression for two-body processes in the interstellar medium (ISM). AIM: The scope of this work is to use first principles to establish the influence of chemical properties on the efficiency of the electron-attachment process for PAHs. METHODS: Quantum multichannel scattering methods are employed to generate the relevant cross sections, hence the attachment rates, using integral elastic cross sections computed over a broad range of relevant energies, from threshold up to 1000 K and linking the attachment to low-energy resonant collisions. RESULTS: The rates obtained for the present molecules are found to markedly vary within the test ensemble of the present work and to be lower than the earlier values used for the entire class of PAHs anions, when modelling their evolutions in ISM environments. The effects of such differences on the evolutions of chemical networks that include both PAH and PAH- species are analysed in some detail and related to previous calculations.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑