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.

提出了对气相悬浮H20和D2O纳米颗粒的熔融和蒸发的实验和计算机化学研究。最初在热平衡中加热颗粒将通过使用红外发射激光源来实现。 HDO将充当颗粒中液相存在的指标。一种新技术，用于生成由不同同位素加热和敏感的FTIR检测组成的由不同同位素组成的分层颗粒和分层颗粒，将首次获得水纳米颗粒的位点依赖性结构信息。特殊努力将针对测量颗粒上准液压层（QLL）的厚度，结构和温度依赖性的研究。 QLL确定颗粒的蒸气压；量子效应的作用将集中在重点上。其他努力也用于研究粒子作为分子自扩散的过程。通过使用激光诱导的爆炸性颗粒蒸发来实现热平衡中的较小尺寸的水簇，每个粒子的2至100个分子的尺寸针对。用于模拟水簇的结构和动力学的计算机代码将用于最多n = 1000分子的大小，并针对与实验程序平行的较大粒子开发。这些代码采用分子动力学，路径积分蒙特卡洛和其他方法。预期的结果对于基础水研究，大气和天文学应用以及分子纳米颗粒的纳米工程应该具有重要意义。