Spectroscopic and Simulation Studies of Ice Surface Interactions with Intermediate and Strong Adsorbates: Physics and Chemistry of Molecular Nanoparticles

俄克拉荷马州立大学的Paul Devlin得到了实验物理化学项目的资助，利用纳米晶体的傅里叶变换红外光谱和大规范蒙特卡罗计算，对独立冰的结构和动力学进行了实验和理论研究。这项工作提供了水分子之间键的强度以及悬垂的、不满足的表面键的性质的信息。详细地说，他正在研究(i)冰表面与强（氨、环氧乙烷、甲醇、小醚、强酸）和中等强度（二氧化硫、硫化氢和氰化物、乙烯）吸收剂的相互作用，（ii）冰纳米晶转化为酸性水合物的定量动力学，（三）小醚分子在帮助冰转化为笼形水合物中的催化作用；（四）探索三维阵列中有机纳米颗粒的化学性质。这些相互作用涉及几个阶段，包括初始吸收、被吸附分子插入弱氢键、表面弛豫和亚表面弛豫或水合物相的形成。这些研究将使我们更详细地了解冰表面的性质，以及不同分子在冰纳米晶体上强弱吸收的机制。这项工作广泛应用于冰粒子在破坏平流层臭氧中的作用，它们在木星冰冷卫星大气日变化中的意义，星际尘埃粒子冰幔的化学性质以及燃料科学中水合物质的控制。

Paul Devlin of Oklahoma State University is supported by a grant from the Experimental Physical Chemistry Program to perform experimental and theoretical studies on the structure and dynamics of free-standing ice using Fourier transform-infrared spectroscopy of nanocrystals and Grand Canonical Monte Carlo calculations. This work is giving information on the strengths of bonds between water molecules and the nature of the dangling, unsatisfied surface bonds. In detail, he is study (i) the interaction the surface of ice with both strong (ammonia, ethylene oxide, methanol, small ethers, strong acids) and intermediate strength (sulfur dioxide, hydrogen sulfide and cyanide, ethylene) absorbates, (ii) the quantitative kinetics of conversion of ice nanocrystals to acid hydrates, (iii) the catalytic role of small ether molecules in aiding the conversion of ice to clathrate hydrates and (iv) an exploration of the chemistry of organic nanoparticles in three dimensional arrays. Several stages are involved in these interactions including initial absorption, insertion of adsorbed molecules into weak hydrogen bonds, surface relaxation and subsurface relaxation or formation of the hydrate phase.These studies will give a more detailed understanding of the nature of the surface of ice and the mechanisms by which different molecules absorb strongly and weakly onto ice nanocrystals. The work has broad applications to the role of ice particles in the destruction of stratospheric ozone, their significance in the diurnal variations of the atmospheres of the icy moons of Jupiter, the chemistry on the ice mantles of interstellar dust particles and the control of hydrated species in fuel science.