Experimental determination of thermal and nonthermal mechanisms for laser desorption from thin metal films
Experimental determination of thermal and nonthermal mechanisms for laser desorption from thin metal films
复制标题
金属薄膜激光解吸热和非热机制的实验测定
DOI：
10.1063/1.458661
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发表时间：
1990
影响因子：
4.4
通讯作者：
J. Hemminger
中科院分区：
文献类型：
--
作者：
Yunzhi Li;R. T. McIver;J. Hemminger
研究了193、248和351 nm激光辐照Au薄膜中肽作为负离子的激光脱附机理。利用阈值激光功率密度随金属膜厚度的变化来区分热机制和非热机制。研究了激光波长对不同光吸收光谱多肽解吸的影响。当使用351 nm激光照射时，观察到热脱附现象。然而，248和193 nm辐射都会导致非热脱附过程。在248 nm处，观察到阈值功率密度与多肽吸附物的光吸收无关，这支持了涉及金属中热电子激发的机制是重要的。
The mechanism of laser desorption of peptides as negative ions from Au thin films with 193, 248 and 351 nm laser radiation has been studied. Variation of the threshold laser power density with metal film thickness is used to distinguish between thermal and nonthermal mechanisms. The influence of laser wavelength on the desorption of peptides with different optical absorption spectra has been studied. Thermal desorption is observed when 351 nm laser radiation is utilized. However, both 248 and 193 nm radiation result in nonthermal desorption processes. At 248 nm, the threshold power density is observed to be independent of the optical absorption of the peptide adsorbate, supporting suggestions that a mechanism involving excitation of hot electrons in the metal is important.