Abstract
We use optical sum-frequency generation to investigate the stretching vibrations of cyanide (CN-) molecules chemisorbed from aqueous electrolytes on single-crystalline Pt(111)- and Pt(110)-electrode surfaces. For clean and well-ordered Pt(111) electrodes, a single vibrational band between 2080 and 2150 cm-1 with a nonlinear frequency dependence on the potential is observed and assigned to the C≡N stretching vibration of chemisorbed cyanide. A second band between 2145 and 2150 cm-1 with very weak potential dependence appears on a surface which was subjected to oxidation-reduction cycles and is attributed to cyanide associated with a microscopically disordered surface. This assignment is supported by preliminary results for a Pt(110) single-crystal electrode. On a well-ordered (110) surface a single and potential-dependent cyanide vibration between 2070 and 2112 cm-1 is observed. After oxidation of the cyanide and readsorption, this band is replaced by a higher frequency band at 2144 cm-1 which is essentially not potential-dependent. Occasionally, additional vibrational bands at lower frequencies not reported in corresponding IR studies are observed on Pt(111).
| Original language | English |
|---|---|
| Pages (from-to) | 553-562 |
| Number of pages | 10 |
| Journal | Applied Physics A Solids and Surfaces |
| Volume | 59 |
| Issue number | 5 |
| DOIs | |
| State | Published - Nov 1994 |
| Externally published | Yes |
Keywords
- 42.62.Fi
- 42.65.Ky
- 68.45.Kg
- 82.65.My