Probing The Origins Of Chemical Complexity

在我们的星球上，生命起源于复杂的化学汤，其起源在某种程度上仍然模糊不清。然而，越来越清楚的是，至少有一部分化学复杂性来自我们太阳系近50亿年前凝聚的致密分子云。已知复杂的有机分子形成于星际尘埃颗粒的冰冷地幔中，这些尘埃颗粒位于如此密集的分子云的寒冷深处，可能是我们原始大气和海洋的种子。在这些寒冷、黑暗的区域，促进化学变化的唯一现实能源是高能（>keV）粒子和光子辐射。这样的辐射在冰质的颗粒地幔中产生了大量的低能二次电子，它们是化学变化的真正媒介。该计划旨在应用定性和定量的表面科学技术和方法来研究在受控低能电子辐照下由极其简单的前体冰混合物（例如H2O/CO，H2O/NH3/CO等）形成复杂有机物。反射-吸收红外光谱（RAIRS），程序升温脱附（TPD）和micrweightgage方法将被结合起来，调查的表面化学状态的演变，而气相产物将被检测的四极质谱（QMS）作为电子能量和束流的函数。

The origins of the complex chemical soup from which life arose on our planet remain to some extent clouded. However, it has become increasingly clear that at least some of that chemical complexity originated from the dense molecular cloud from which our solar system condensed nearly 5 billion years ago. Complex organic molecules are known to be formed in the icy mantles of interstellar dust grains in the cold depths of such dense molecular clouds and may have seeded our primordial atmosphere and oceans. In these cold, dark regions, the only realistic energy source for promotion of chemical change is high energy (>keV) particle and photon radiation. Such radiation generates within the icy grain mantles a shower of low energy secondary electrons that are the true agents of chemical change. This programme seeks to appy both qualitative and quantitative surface science techniques and methodolgies to investigate the formation of complex organics from extremely simple precursor ice mixtures, e.g. H2O/CO, H2O/NH3/CO etc. under controlled low energy electron irradiation. Reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD) and micrgravimetric methods will be combined to investigate the evolution of the surface chemical state while gas phase products will be detected by quadrupole mass spectrometry (QMS) as a function of both electron energy and beam current.