Thiam Michel Malick, Kondo Takahiro, Horimoto Noriko, Kato Hiroyuki S, Kawai Maki
RIKEN (The Institute of Physical and Chemical Research), Wako 351-0198, Japan.
J Phys Chem B. 2005 Aug 25;109(33):16024-9. doi: 10.1021/jp052167q.
The initial growth of a water (D2O) layer on (1 x 1)-oxygen-covered Ru(0001) has been studied in comparison with that on bare Ru(0001) by means of temperature-programmed desorption (TPD) and infrared reflection absorption spectroscopy (IRAS). Although water molecules adsorbed on both bare and (1 x 1)-oxygen-covered Ru(0001) commonly tend to form hydrogen bonds with each other when mobility occurs upon heating, the TPD and IRAS measurements for the two surfaces exhibit distinct differences. On (1 x 1)-oxygen-covered Ru(0001), most of the D2O molecules were desorbed with a peak at 160 K, even at submonolayer coverage, as condensed water desorption. The vibration spectra of adsorbed D2O also showed broad peaks such as a condensed water phase, from the beginning of low coverage. For submonolayer coverage, in addition, we found a characteristic O-D stretching mode at around 2650 cm(-1), which is never clearly observed for D2O on bare Ru(0001). Thus, we propose a distinctive water adsorption structure on (1 x 1)-oxygen-covered Ru(0001) and discuss its influence on water layer growth in comparison with the case of D2O on bare Ru(0001).
通过程序升温脱附（TPD）和红外反射吸收光谱（IRAS），研究了在（1×1）氧覆盖的Ru(0001)上生长的水（D₂O）层，与在裸Ru(0001)上生长的水层进行了比较。尽管吸附在裸Ru(0001)和（1×1）氧覆盖的Ru(0001)上的水分子在加热时发生迁移时通常倾向于相互形成氢键，但两个表面的TPD和IRAS测量结果显示出明显差异。在（1×1）氧覆盖的Ru(0001)上，即使在亚单层覆盖时，大多数D₂O分子也会在160 K处出现一个脱附峰，如同冷凝水脱附。吸附的D₂O的振动光谱从低覆盖开始就显示出宽峰，如冷凝水相。此外，对于亚单层覆盖，我们在约波数2650 cm⁻¹处发现了一个特征性的O-D伸缩模式，这在裸Ru(0001)上的D₂O中从未清晰观察到。因此，我们提出了在（1×1）氧覆盖的Ru(0001)上一种独特的水吸附结构，并与裸Ru(0001)上D₂O的情况相比，讨论了其对水层生长的影响。
