Laser-Induced Phase Transitions in Gas-Phase Suspended Molecular Nanoparticles

气相悬浮分子纳米颗粒中激光诱导的相变

• 批准号: 24101151
• 负责人: Professor Dr. Karl-Heinz Gericke
• 金额: --
• 依托单位: Institut für Physikalische und Theoretische Chemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/24101151?language=en
• 关键词: Laser; Induced; Phase; Transitions; Gas

Experimental and computer-chemical investigation of melting and vaporisation of gas-phase suspended H20 and D2O nanoparticles is proposed. The heating of the particles being initially in thermal equilibrium will be realized by use of infrared-emitting laser sources. HDO will act as an indicator for presence of the liquid phase in the particles. A new technique for generation of mantle-core particles and layered particles composed of different isotopomers, combined with laser heating and sensitive FTIR detection, will allow to get site-dependent structure information for water nanoparticles for the first time. Special efforts will be directed on the investigation of thickness, structure and temperature dependence of the quasi-liquid-layer (QLL) on the particles. The QLL determines the vapour pressure of the particles; the role of quantum effects will be on focus. Other efforts are addressed to study processes of the particles as molecular self-diffusion. Smaller sizes of water clusters in thermal equilibrium with 2 to 100 molecules per particle are aimed for by use of laser-induced explosive particle vaporisation. A bank of computer codes for simulating structure and dynamics of water clusters will be applied for sizes up to n = 1000 molecules and developed for bigger particles parallel to the experimental program. The codes apply Molecular Dynamics, Path Integral Monte Carlo and other methods. The expected results should have major importance to basic water research, to atmospheric and astro-chemical applications as well as to nanoengineering of molecular nanoparticles.

提出了气相悬浮 H2O 和 D2O 纳米颗粒熔化和蒸发的实验和计算机化学研究。最初处于热平衡的颗粒的加热将通过使用红外发射激光源来实现。 HDO 将充当颗粒中是否存在液相的指示剂。一种生成由不同同位素组成的地幔核颗粒和层状颗粒的新技术，结合激光加热和灵敏的 FTIR 检测，将首次获得水纳米颗粒的位点相关结构信息。将特别致力于研究颗粒上准液体层（QLL）的厚度、结构和温度依赖性。 QLL 确定颗粒的蒸气压；量子效应的作用将成为焦点。其他努力致力于研究粒子作为分子自扩散的过程。通过使用激光诱导爆炸性颗粒汽化，可以实现更小尺寸的水簇的热平衡，每个颗粒有 2 至 100 个分子。一组用于模拟水簇结构和动力学的计算机代码将适用于 n = 1000 个分子的大小，并与实验程序并行开发更大的颗粒。代码应用了分子动力学、路径积分蒙特卡罗等方法。预期结果对于基础水研究、大气和天体化学应用以及分子纳米粒子的纳米工程具有重要意义。