Does the Sum-Frequency Generation Signal of Aromatic C-H Vibrations Reflect Molecular Orientation?

ABSTRACT: Organic molecules with aromatic groups at the aqueous interfaces play a central role in atmospheric chemistry, green chemistry, and on-water synthesis. Insights into the organization of interfacial organic molecules can be obtained using surface-specific vibrational sum-frequency generation (SFG) spectroscopy. However, the origin of the aromatic C-H stretching mode peak is unknown, prohibiting us from connecting the SFG signal to the interfacial molecular structure. Here, we explore the origin of the aromatic C-H stretching response by heterodyne-detected SFG (HD-SFG) at the liquid/vapor interface of benzene derivatives and find that, irrespective of the molecular orientation, the sign of the aromatic C-H stretching signals is negative for all the studied solvents. Together with density fu

SUBMITTER: Matsumura F 

PROVIDER: S-EPMC10278126 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature