Fig. 4. Optical absorption spectra of Au₆₈(SH)₃₂.

Top row: The experimental (wine and olive) curves and the theoretical (black) curve plotted by taking the data from Ref. 20. Rows 2 to 5: Computed optical absorption spectra of Iso1 to Iso4. The red curve denotes the vibrational frequency analysis based on the individual vibrational intensities (red vertical lines). The blue curve denotes spectra from TD-DFT computation of the individual optical transitions. In all five rows, the locations of four prominent absorption peaks (a, b, c, and d), from either experiment or theory, are displayed.