A computational study on surface-enhanced Raman spectroscopy of para-substituted Benzenethiol derivatives adsorbed on gold nanoclusters

• Bridge- and vertex-type x-Benzenethiol/Au13 complexes was investigated via DFT calculations.
• Off-resonance spectral enhancement varied with substitutions and configuration.
• Electronic and excitation properties were collected to compare with enhancement.
• Results indicated that off-resonance and on-resonance effect were with similar origination.

We presented a computational study on para-substituted Benzenethiol (x-BT, x = H, F, Cl, Br, OH, SH, SeH, NH2, CH3) derivatives interacting with gold cluster for chemical effects related to surface-enhanced Raman spectroscopy (SERS). Density functional theory (DFT) calculations were performed on a series of bridge-type and vertex type x-BT/Au13 complexes for geometric, electronic and excitation properties to determine the key factor in spectral enhancement. Results indicated that off-resonance enhancement factors of bridge-type and vertex-type complexes exhibited different dependency on substitutions, which was greatly influenced by molecule–cluster transitions instead of properties such as interaction energy and charge transfer due to same origination for off-resonance and resonance chemical enhancement.

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