Time-Resolved Studies of Coherent Surface Optical Phonons and Low Frequency Adsorbate-Substrate Vibrations

相干表面光学声子和低频吸附基质振动的时间分辨研究

• 批准号: 9707143
• 负责人: Harry Tom
• 金额: $ 40.7万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9707143&HistoricalAwards=false
• 关键词: Time; Resolved; Studies; Coherent; Surface

In this project of the Experimental Physical Chemistry Program in the Chemistry Division with support for instrumentation from the Office of Multidisciplinary Activities, Prof. Harry Tom will develop and characterize a new type of coherent spectroscopy for surface optical phonons and for low frequency adsorbate-substrate vibrational modes. The work here will establish general mechanisms for creating and detecting coherent phonon oscillations on a large number of surfaces. Establishing the energy and dephasing relaxation times for these low frequency modes is an outstanding problem in surface dynamics. Both semiconductor (GaAs and Si) and metal (Cu and alkali-covered Cu) surfaces will be examined. The time-resolved surface second-harmonic generation signal (TRSHG) technique to be developed here has several advantages over existing spectroscopic techniques, such as better spectral resolution and higher signal-to-noise ratio, and it is the only coherent technique for studying surface phonons.

在化学学部实验物理化学计划的这个项目中，在多学科活动办公室仪器的支持下，Harry Tom教授将开发并表征一种新型的表面光学声子和低频吸附-衬底振动模式的相干光谱。这里的工作将建立在大量表面上产生和检测相干声子振荡的一般机制。建立这些低频模式的能量和消相弛豫时间是表面动力学中的一个突出问题。半导体（砷化镓和硅）和金属（铜和碱覆盖的铜）表面将被检查。本文开发的时间分辨表面二次谐波产生信号（TRSHG）技术与现有的光谱技术相比，具有更高的光谱分辨率和更高的信噪比等优点，是研究表面声子的唯一相干技术。