MOLECULAR ORDERING OF ORGANOSULFUR COMPOUNDS ON AU(111) AND AU(100) - ADSORPTION FROM SOLUTION AND IN ULTRAHIGH-VACUUM
MOLECULAR ORDERING OF ORGANOSULFUR COMPOUNDS ON AU(111) AND AU(100) - ADSORPTION FROM SOLUTION AND IN ULTRAHIGH-VACUUM
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DOI：
10.1063/1.464613
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发表时间：
1993-01-01
影响因子：
4.4
通讯作者：
NUZZO, RG
中科院分区：
文献类型：
--
作者：
DUBOIS, LH;ZEGARSKI, BR;NUZZO, RG
用低能电子衍射和反射吸收红外光谱研究了正构硫醇[HS（CH 2）mCH 3]在（111）和（100）单晶金基底上的吸附。通过从溶液（m = 15、17、18和21）或在真空中（m = 0-9）给药制备样品。在Au（111）上，获得了有序的表面结构，其可以被索引为（n平方根3 X平方根3）R30度，其中n从1变化到6。在Au（100）面上，短链硫醇的吸附导致形成c（2 × 2）的覆盖层，而长链硫醇则显示出额外的衍射斑点分裂。它也被发现，链长的影响看到的衍射的字符和扰动的反应性粘在超高真空剂量的分子的概率。红外光谱研究表明，在Au（100）上形成的单分子膜的聚亚甲基链几乎由全反式构象组成，并且比在Au（111）上形成的类似结构倾斜更小。提出了一个简单的模型来解释这两个表面上的差异，并提出了有机硫醇在金上吸附和组装成有序单层相的机制。
Low-energy electron diffraction and reflection-absorption infrared spectroscopy were used to study the monolayers formed by the adsorption of n-alkane thiols [HS(CH2)mCH3] on both (111) and (100) single-crystal gold substrates. Samples were prepared by dosing either from solution (m = 15, 17, 18, and 21) or in ultrahigh vacuum (m = 0-9). On Au(111), ordered surface structures are obtained which can be indexed as (n square-root 3 X square-root 3)R30-degrees, where n varies from 1 to 6. On Au (100), the adsorption of short chain thiols leads to the formation of a c(2 X 2) overlayer while the longer chain homologs show additional diffraction spot splittings. It is also found that chain length influences both the character of the diffraction seen and perturbs the reactive sticking probability of molecules dosed in UHV. Infrared studies reveal that the polymethylene chains of the monolayers formed on Au(100) are comprised of nearly all-trans conformations and are less canted than the comparable structures formed on Au(111). A simple model is proposed to account for the differences seen on the two surfaces and a mechanism for the adsorption and assembly of organic thiols into ordered monolayer phases on gold is presented.