Electronic Supplementary Information for: A Mechanistic Study of the Electrochemical Oxygen Reduction on the Model Semiconductor n-Ge(100) by ATR-IR and DFT

1 Experimental vibrational frequencies of reference compounds 1.1 Oxygen-containing species 1.1.1 Raman spectra of KO2 and O2 Stable superoxides can be used to check the vibrational frequencies obtained from DFT calculations. To that end, the Raman spectrum of KO2 powder (ABCR, Karlsruhe, Germany) on a Si wafer was recorded using a Horiba Labram 2 confocal Raman microscope with 633 nm excitation. The spectrum is shown in Figure 1a, with peak maximum at 1145 cm.