چکیده (انگلیسی):

The purpose of this work was to study the effects of crystal
structure on the solid-state photoluminescence of the trihydrate
phases of ampicillin and amoxicillin, and to contrast
these spectra with analogous spectra obtained on the
molecules dissolved in a solution phase. The polymorphic
identity of the analytes was established using x-ray powder
diffraction and Fourier transform infrared absorption
spectroscopy, and the solid-state luminescence spectra obtained
under ambient conditions. It was found that the
solid-state excitation and emission spectra of ampicillin
trihydrate and amoxicillin trihydrate were dominated by
energy transfer and exciton effects, which were manifested
as decreases in the energy of the excitation and emission
bands of the solid-state systems relative to those of the free
molecule in solution. The photoluminescence data revealed
that in spite of the known structural similarity of ampicillin
trihydrate and amoxicillin trihydrate, the magnitude of
the Davydov splitting, and the degree of band energy shifting
differed between the 2 systems. This finding indicates
that the small differences in crystal structure existing between
the 2 compounds leads to measurable differences in
the patterns of energy transfer.