Travel Grant to perform Photoionisation Studies on small Reactive Intermediates at the Elettra (Trieste) synchrotron facility

分子自由基是基电子态电子数不成对的分子。正因为如此，他们具有高度的反应性。它们在等离子体、燃烧和地球大气等环境中很重要，因为它们的反应性，它们通常以低浓度存在。然而，它们在控制最终的化学产物和在这些环境中观察到的主要化学路径方面发挥着重要作用。在这项工作中将测量的分子自由基的电离能导致离子的形成热和中性分子键离解能的确定，这可以用于诸如等离子体、火焰和地球大气等环境的模型。将以地球大气中离子的产生为例：-太阳进入地球大气的辐射由连续的(黑体)分布以及几条离散的线组成。这种辐射的一部分具有足够的能量，可以直接(即非共振地)电离大气中的分子自由基。另一种电离机制包括产生高于第一离子极限的高度激发的中性态(里德堡态)，然后可以电离。详细研究这些非共振和共振过程，对于理解地球大气中处于不同电子和振动状态的离子的产生非常重要。分子自由基产生的分子离子在等离子体、燃烧和溶液中也很重要，如本项目所建议的，通过光谱手段研究它们，并辅之以电子结构计算，有助于了解它们的结构和性质，从而了解它们在这些环境中的行为。综上所述，分子自由基光电离过程是非常重要的，在许多科学领域都有应用，包括天体物理、行星科学、地球大气化学、辐射化学、物理和生物学。这些领域的工作者需要电离能和有关电子激发的中性态和低电离态的信息，以及宽光谱范围内光吸收和光电离(相对和绝对截面)的强度测量。这些信息在这些环境的计算机模拟和建模中特别有用。

Molecular radicals are molecules with an unpaired number of electrons in their ground electronic states. Because of this they are highly reactive. They are important in environments such as plasmas, combustion and the earth's atmosphere where because of their reactivity, they are often present in low concentrations. However, they play a major role in controlling the final chemical products and dominant chemical pathways observed in these environments. Ionization energies of molecular radicals, which will be measured in this work, lead to determination of heats of formation of ions and neutral molecule bond dissociation energies which can be used in models of environments such as plasmas, flames and the earth's atmosphere. The production of ions in the earth's atmosphere will be taken as an example:-Radiation from the sun entering the earth's atmosphere consists of a continuous (black-body) distribution as well as several discrete lines. A part of this radiation is sufficiently energetic to ionize molecular radicals in the atmosphere directly (i.e. non-resonantly). Another mechanism of ionisation involves production of a highly excited neutral state (a Rydberg state), above the first ionic limit which can then ionize. Studying these non-resonant and resonant processes in detail is important in terms of understanding the production of ions in different electronic and vibrational states in the earth's atmosphere. Molecular ions produced from molecular radicals are also important in plasmas, combustion and solution, and studying them via spectroscopic means, supported by electronic structure calculations, as proposed in this project helps to understand their structure and properties, and hence behaviour in these environments. In summary, photoionization processes of molecular radicals are of fundamental importance, and find application in a large number of scientific areas, including astrophysics, planetary science, the chemistry of the earth's atmosphere, radiation chemistry, physics and biology. Workers in these fields require ionisation energies and information on electronic excited neutral states and low-lying ionic states, as well as measures of intensities for photoabsorption and photoionization ( relative and absolute cross-sections) over a wide spectral range. This information is particularly useful in computer simulations and modelling of these environments.