| Summary: | 碩士 === 國立臺灣師範大學 === 化學研究所 === 92 === The adsorption and thermal desorption of stilbene on Ag/Ge(111) -(√3×√3)R30° (Ag/Ge-√3) have been studied using the combination techniques of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), and temperature programmed desorption (TPD).
The Ag/Ge-√3 surface was prepared by thermal deposition of Ag onto Ge(111) substrate of 100 K, followed by postannealing to 500 K for 2 min. The 1ML Ag coverage, was estimated from AES measurements. The surface structure was confirmed by LEED.
At coverages of 1 monolayer, TPD studies showed that for cis-stilbene(CSB) molecular desorption two peaks were observed at Tp(peak temperature)=243K、275K, which are attributed to multilayer and monolayer desorption, respectively. TPD traces of trans-stilbene(TSB) show only one single peak at Tp(peak temperature)= 282K, which can be attributed to the overlapping monolayer and mutilayer desorption peaks. No other thermal desorption products were detected during the heating process.
From the coverage dependent analysis of TPD spectra, it was found that the desorption of CSB and TSB from Ag/Ge-√3 exhibits half-order desorption kinetics, suggesting the desorption starts from the circumstance. These results are compared to the previous STM study (Langmuir, 2003, 19, 822-829) in which the structure of CSB cluster formed on Ag/Ge-√3 upon annealing was reported.
|
|---|
