Time Resolved Spectroscopy of Complex Materials

9710140纳尔逊 本提案的目的是实现一个改进的基本理解的动力学和结构演变的非晶和部分无序材料。 在皮秒到毫秒范围内的过冷液体的密度动力学将被检查，连同模式耦合的过冷液体行为的理论预测。 线性和（主要是）非线性晶格动力学结构相变附近的晶体将被研究，以阐明非谐晶体势能面，决定相变机制以及相变的动力学短激光脉冲的影响下。 还将使用激光产生的声波对薄膜结构进行测量，以进行粘附力的系统研究，并开发一种新型的图案化薄膜和薄膜-基底组件的光声成像，例如用于微电子学的薄膜-基底组件。 对凝聚材料的理解，如玻璃形成液体和具有粘性液体客人的溶胶-凝胶玻璃，对涉及依赖于块体和薄膜材料应用的各种技术的进步的行业具有巨大的重要性。 例如，该项目将开发新技术，首次对高度空间分辨的薄膜基板结构中的粘附力学进行全面表征，研究短激光脉冲影响下的半导体转变，以及玻璃形成液体中的密度动态，这将允许对理论预测进行更全面的测试，并为理论发展提供额外的指导。

9710140 Nelson The aim of this proposal is to achieve an improved fundamental understanding of the dynamical and structural evolution of amorphous and partially disordered materials. Density dynamics of super cooled liquids in the picosecond through millisecond range will be examined, together with the mode-coupling theoretical predictions of supercooled liquid behavior. Linear and (primarily) nonlinear lattice dynamics in crystals near structural phase transitions will be studied to elucidate anharmonic crystalline potential energy surfaces that dictate phase transition mechanisms as well as the dynamics of phase transitions under the influence of short laser pulses. Measurements will also be conducted on thin film structures using laser generated acoustic waves to carry out a systematic study of adhesion, and to develop a new kind of photoacoustic imaging of patterned films and film-substrate assemblies such as those used in microelectronics. %%% An understanding of condensed materials such as glass forming liquids and sol-gel glasses with viscous liquid guests are of tremendous importance to industries involved with the advancement of various technologies dependent on both bulk and thin film materials applications. For example, this project will develop new techniques that will allow for the first-time a thorough characterization of adhesion mechanics in highly spatially resolved film substrate structures, the study of semiconductor transitions under the influence of short laser pulses, and density dynamics in glass forming liquids that will allow more complete testing of theoretical predictions and additional guidance for theoretical development.