Visualizing spatially decomposed intermolecular correlations in the infrared spectra of aprotic liquids

Infrared (IR) spectroscopy is commonly used to study intermolecular interactions in the liquid phase, including solvation phenomena. On the other hand, ab initio molecular dynamics (AIMD) simulations offer the possibility to obtain IR spectra from first principles. Surpassing the experiment, AIMD simulations can deliver additional information on the spatial intermolecular correlations underlying the IR spectrum of the liquid. Although such correlations contribute significantly to the IR spectra of associated liquids, such as water, they are equally important in the case of aprotic solvents, where dipole-dipole interactions are dominant. Here, the extent and non-trivial character of the spatial correlations in the IR spectra are demonstrated on the example of γ-butyrolactone (GBL), an important solvent in the rechargeable cell industry.