Vibrational Line Broadening Mechanisms for Molecules Adsorbed on Metal Surfaces

金属表面吸附分子的振动线展宽机制

• 批准号: 8907398
• 负责人: Michael Trenary
• 金额: $ 25.67万
• 依托单位: University of Illinois at Chicago
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-08-15 至 1993-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8907398&HistoricalAwards=false
• 关键词: Vibrational; Line; Broadening; Mechanisms; Molecules

This project is in the general area of analytical and surface chemistry and in the subfield of surface vibrational spectroscopy. High resolution vibrational spectra of a variety of molecular species adsorbed on metal surfaces will be measured using Fourier transform infrared reflection-absorption spectroscopy (FT-IRAS). The limits of IRAS will be extended: 1) to study adsorbate-substrate vibrations; 2) to characterize the temperature dependence of vibrational line shapes at temperatures as low as 10 K; 3) to characterize the line shapes of overtones; 4) to characterize and analyze the influence of order-disorder phase transitions on adsorbate lineshapes. Chemical systems to be studied include the molecular species phosphorus trifluoride, carbon monoxide and ethylidyne on single-crystal faces of platinum and nickel. The intrinsic lineshapes of vibrational spectra contain information on adsorbate-adsorbate interactions, the extent of vibrational coupling to other modes, and the lower bound of other vibrational modes. The wide range of temperatures that will be employed in this study and the possibility of freezing out phonon mechamisms will permit discrimination among various competing mechanisms of line broadening.

该项目属于分析和表面化学的一般领域以及表面振动光谱学的子领域。 将使用傅里叶变换红外反射吸收光谱（FT-IRAS）测量金属表面吸附的各种分子的高分辨率振动光谱。 IRAS 的限制将扩大： 1) 研究吸附质-基质振动； 2) 表征低至 10 K 温度下振动线形状的温度依赖性； 3）表征泛音的线形； 4）表征和分析有序-无序相变对吸附物线形的影响。 待研究的化学系统包括铂和镍单晶面上的分子物质三氟化磷、一氧化碳和乙炔。 振动光谱的固有线形包含有关吸附物-吸附物相互作用、与其他模式的振动耦合程度以及其他振动模式的下限的信息。 本研究中将采用的大范围温度以及冻结声子机制的可能性将允许区分谱线展宽的各种竞争机制。