Laboratory Measurements of N2 Reacting with H3+ Isotopologues and Implications for Deuterated Astrochemistry

分子观测对于理解星际气体如何转化为分子云、恒星和行星非常重要。 该研究项目将调查分子离子N2H+和N2D+的形成，这些离子通常用于追踪星前分子云和原行星盘的性质。通过一项复杂的实验室实验，研究人员将准确地确定与星际云相关的极低温度下离子的产生速率。这项研究的结果将使天文学家能够准确地确定这些离子在太空中的丰度，并解释星星和行星形成的最早阶段的观测结果。 该项目将有助于博士后的培养和专业发展，为本科生提供研究机会，并通过天体化学讲座吸引公众参与。Savin和合作者将使用双源合并快束装置测量N2与H3+及其氘代形式的六个反应的精确积分截面（ICS），作为反应物内部温度的函数。 ICS将使团队能够生成可靠的N2 H+和N2 D+形成热速率系数，用于天体化学模型。 这些测量结果也将指导实验室数据不可用的氘代分子的天体化学模型，它们将测试用于解释部分氘代分子在太空中的分支分数的近似值的有效性。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Molecular observations are important to understanding how the interstellar gas is converted to molecular clouds, stars, and planets. This research project will investigate the formation of the molecular ions N2H+ and N2D+, which are commonly used to trace properties of prestellar molecular clouds and protoplanetary disks. By means of a sophisticated laboratory experiment, the investigators will accurately determine the production rates of the ions at the very low temperatures relevant to interstellar clouds. Results from the study will allow astronomers to accurately determine the abundance of these ions in space and interpret observations of the earliest stages of star and planet formation. This project will contribute to the training and professional development of a postdoctoral scholar, provide research opportunities for undergraduates, and engage the public through lectures on astrochemistry.Using a dual-source, merged fast-beams apparatus, Savin and collaborators will measure accurate integral cross sections (ICS) for six reactions of N2 with H3+ and its deuterated forms as a function of the internal temperature of the reactants. The ICSs will allow the team to generate reliable thermal rate coefficients for N2H+ and N2D+ formation for use in astrochemical models. The measurements will also guide astrochemical models of deuterated molecules for which laboratory data are unavailable, and they will test the validity of approximations used to interpret branching fractions of partially deuterated molecules in space.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.