Computational dataset of cetyl trimethyl ammonium-anion complex structures and simulated infrared spectra.

This dataset presents computationally derived geometries and vibrational spectra of cetyl trimethyl ammonium ion pairs formed with three environmentally and chemically relevant anions: bisulfate, nitrate, and methyl sulfonate. Data were obtained using quantum chemical calculations performed using the Gaussian 16 software package, utilizing the ONIOM method at the second-order Møller-Plesset perturbation theory (MP2) level. To account for solvent effects and electrostatic screening, calculations incorporated an implicit solvent environment via the polarizable continuum model (PCM). The dataset includes optimized geometric coordinates, harmonic vibrational frequencies, and simulated infrared (IR) spectra for each cetyl trimethyl ammonium-anion pair. Additional computational details, including input parameters, computational settings, and scripts used for data processing, are provided as supplementary material to ensure complete transparency and reproducibility. Data collection involved initial construction and optimization of the molecular geometries of ion pairs, followed by calculation of vibrational modes at equilibrium. Distance-displacement scans were conducted and the ONIOM total electronic energies and geometries of these non-stationary structures are reported. This comprehensive dataset offers significant reuse potential for researchers investigating surfactant chemistry, computational spectroscopy, environmental chemistry, and related disciplines.