Structure, Energetics, Reaction Dynamics and Vibrational Spectra of Gaseous Ions

气态离子的结构、能量学、反应动力学和振动谱

• 批准号: RGPIN-2016-04142
• 负责人: McMahon, Terrance
• 金额: $ 3.35万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709005
• 关键词: Structure; Energetics; Reaction; Dynamics; Vibrational

The general objectives of our research over the next grant period will be to expand the understanding of the nature of inter- and intra-molecular interactions found in the novel bonding environments frequently displayed by gas phase ions and to probe both the unimolecular and bimolecular reaction dynamics of gas phase ions. In order to address these objectives we will use a four-pronged approach combining both experimental and computational studies. The first of the experimental methods used is High Pressure Mass Spectrometry (HPMS), which permits the study of gas-phase ion-molecule reactions and equilibria as a function of temperature. In this way, accurate experimental values of Ho and So can be obtained for these processes leading to an accurate, quantitative understanding of the potential energy landscapes involved. The second experimental approach involves Fourier Transform Ion Cyclotron Resonance Spectrometry (FTICR) which permits confinement of ions in an electromagnetic trap for extremely long periods of time at low pressures. The third technique exploited is Infrared Multiple Photon Dissociation (IRMPD) experiments involving a Free Electron Laser (FEL). Finally, all of our experimental work is accompanied by computational studies using electronic structure methods which greatly aid in the understanding of bonding and energetics as well as in the interpretation of vibrational spectra. An accompanying RTI application also proposes to add an OPO laser system to our laboratory to permit IRMPD experiments to be carried out at Waterloo. The principle experiments to be carried out are of several different types. We have demonstrated recently the significant insight into small biomolecule structure and dynamics that can be gained from gas phase bimolecular H/D reactions using FTICR experiments. As an example, the Na+(Ala)n series of sodiated polyalanines (n = 2-14) have been found to exhibit a surprising consistency in the number and speed of H/D exchange dynamics despite significant changes in the structures of the polyalanines as the number of amino acid residues increases. H/D exchange experiments are also currently in progress for protonated glutathione and its protonated dimer. Another area of study involves the formation and characterization of some novel gas phase clusters. We are investigating a series of alkylammonium chlorides which show the capability of forming extended networks resembling the formation of salt crystals in the gas phase. In addition, guanidinium chloride is found to form very large clusters which take on progressively greater extents of bowl and ball like shapes as the cluster size increases. Finally, a new type of systems involving ionic adducts of all-cis hexafluorocyclohexane and related substituted cyclohexanes are under investigation as they exhibit extremely strong ion binding interactions. IRMPD spectra aid in their characterization.

我们在下一个资助期的研究的总体目标将是扩大对在气相离子经常显示的新型键合环境中发现的分子间和分子内相互作用的性质的理解，并探索气相离子的单分子和双分子反应动力学。为了实现这些目标，我们将采用实验和计算研究相结合的四管齐下的方法。使用的第一种实验方法是高压质谱法（HPMS），它允许研究气相离子-分子反应和平衡作为温度的函数。通过这种方式，可以获得这些过程中Ho和So的精确实验值，从而准确定量地了解所涉及的势能景观。第二种实验方法涉及傅立叶变换离子回旋共振光谱（FTICR），它允许在低压下将离子限制在电磁阱中极长时间。第三种利用的技术是红外多光子解离（IRMPD）实验，涉及自由电子激光（FEL）。最后，我们所有的实验工作都伴随着使用电子结构方法的计算研究，这对理解键和能量学以及解释振动谱有很大的帮助。随附的RTI申请还建议在我们的实验室添加一个OPO激光系统，以允许在滑铁卢进行IRMPD实验。