An advanced molecular-beam surface-scattering apparatus for studies under extreme conditions

我们提出了一种先进的分子束表面散射仪，优化了在极端条件下的研究。该仪器在以下参数方面远远超过我们现有机器的能力：1)极端表面温度和极端入射能量的可访问性，2)通过光学方法(REMPI；软真空紫外光电离)以及电子碰撞电离质谱仪进行产品检测，3)用于反应散射的双分子束几何结构，以及4)与现有纳米颗粒软着陆设备的接口。新仪器将扩展我们对天生奥本海默击穿的理解，因为它将使大量能量(高温、高平移能量)在分子和表面之间交换的研究成为可能。新类型的反应(例如通过质子转移的表面电离)也是可能的。对反应散射的研究将阐明非绝热影响在化学反应中的重要性，即显示电子和核(振动)自由度之间的能量流动如何抑制或加强化学反应。将使用表面耦合量子井结构来研究化学能量到光能的转换-这是一个迄今未被观察到的通道。

We propose an advanced molecular-beam surface-scattering apparatus optimzed for studies under extreme conditions. This instrument goes well beyond the capabilities of our existing machine with regard to the following parameters: 1) accessability of extreme surface temperatures and extreme incidence energies, 2) product detection by optical methods (REMPI; soft VUV photoionization) as well as electron impact ionization mass spectrometry, 3) dual molecular beam geometry for reactive scattering, and 4) interfacing with an existing nanoparticle soft-landing apparatus. The new instrument will extend our understanding of Born Oppenheimer breakdown as it will enable studies where large amounts of energy (high temperature, high translational energy) are exchanged between a molecule and the surface. New types of reactions (e.g. surface ionization by proton transfer) are also possible. Studies on reactive scattering will elucidate the importance of nonadiabatic influence in chemical reactions, i.e. show how the energy flow between the electronic and nuclear (vibrational) degrees of freedom suppresses or enhances chemical reactions. Conversion of chemical to optical energy – a so far unobserved channel – will be studied using surface-coupled quantum well structures.