Vibrational sum-frequency spectra (VSFS) were modeled computationally using time dependent density functional theory (TDDFT) for a range of dicarboxylic acids and other organic compounds present in atmospheric aerosols. The interface sensitive technique, VSFS, provides important information about the surface of aerosols determining how they interact with external species. Second order linear susceptibilities were determined from the product of polarizability and dipole moment derivatives for each normal mode. Spectra were calculated for molecules in the gas phase and interacting with a small number of explicit waters. Spectral analysis of SSP and SPS polarized VSFS spectra reveals the effect of the number of explicit waters and molecular orientation. Calculated spectra were consistent with previous experimental spectra and orientations determined from molecular dynamics calculations while elucidating and confirming the bonding environment of these atmospherically relevant molecules.

Modeling vibrational sum-frequency spectra of dicarboxylic acids at the water/air interface

245th National Meeting (2013)

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