Rzeźnicka Izabela I, Lee Junseok, Maksymovych Petro, Yates John T
Surface Science Center, Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Phys Chem B. 2005 Aug 25;109(33):15992-6. doi: 10.1021/jp058124r.
The adsorption of methanethiol and n-propanethiol on the Au(111) surface has been studied by temperature-programmed desorption (TPD), Auger electron spectroscopy (AES), and low-temperature scanning tunneling microscopy (LT-STM). Methanethiol desorbs molecularly from the chemisorbed monolayer at temperatures below 220 K in three overlapping desorption processes. No evidence for S-H or C-S bond cleavage has been found on the basis of three types of observations: (1) A mixture of chemisorbed CH3SD and CD3SH does not yield CD3SD, (2) no sulfur remains after desorption, and (3) no residual surface species remain when the adsorbed layer is heated to 300 K as measured by STM. On the other hand, when defects are introduced on the surface by ion bombardment, the desorption temperature of CH3SH is extended to 300 K and a small amount of dimethyl disulfide is observed to desorb at 410 K, indicating that S-H bond scission occurs on defect sites on Au(111) followed by dimerization of CH3S(a) species. Propanethiol also adsorbs nondissociatively on the Au(111) surface and desorbs from the surface below 250 K.
通过程序升温脱附（TPD）、俄歇电子能谱（AES）和低温扫描隧道显微镜（LT-STM）研究了甲硫醇和正丙硫醇在Au(111)表面的吸附情况。甲硫醇在低于220 K的温度下以三种重叠的脱附过程从化学吸附的单分子层中分子态脱附。基于以下三种观察结果，未发现S-H或C-S键断裂的证据：（1）化学吸附的CH3SD和CD3SH的混合物不会产生CD3SD，（2）脱附后没有硫残留，（3）通过STM测量，当吸附层加热到300 K时没有残留的表面物种。另一方面，当通过离子轰击在表面引入缺陷时，CH3SH的脱附温度扩展到300 K，并且观察到少量二甲基二硫在410 K脱附，这表明S-H键在Au(111)表面的缺陷位点发生断裂，随后CH3S(a)物种发生二聚化。正丙硫醇也以非解离方式吸附在Au(111)表面，并在低于250 K的温度下从表面脱附。
