Fig. 2

Consecutive spectra of caprylic acid (C8) after deposition on a pure copper surface and b copper-zinc alloy surface; insets: zoom in the carbonyl-carboxylate region. The region 1780–1480 cm⁻¹ from the spectra after compensation for loss due to evaporation of C8 after deposition on c pure copper surface and d copper-zinc alloy surface (see Materials and Methods, 2.2.2). In all cases, consecutive spectra were recorded at ~ 20 °C and RH 40%; time in (c) is given in hours:minutes