Low-Frequency Vibrational Spectra of Amoxicillin and Ampicillin

Amoxicillin and ampicillin are large, flexible antibiotic molecules that are commonly administered in their solid trihydrate forms. The hydration of these pharmaceuticals has been studied in this work using both terahertz and low-frequency Raman vibrational spectroscopies to measure the vibrational modes of the crystalline solids below 200 cm
^-1
. Combining the experimental results with solid-state density functional theory simulations of both structure and vibrations, allows for the in-depth exploration of the potential energy surfaces governing the large-amplitude motions of the co-crystalized waters.