Manifestation of Vacancies in a Spectrum of Organic Molecular Crystal Lattice Vibrations

TL;DR

This study uses Raman spectroscopy to analyze how vacancies in organic molecular crystals affect lattice vibration spectra, revealing size-dependent vacancy-related spectral lines and their intensities.

Contribution

It demonstrates that vacancy-related spectral lines vary with crystal size and vacancy concentration, providing a method to identify vacancies via Raman spectra.

Findings

Vacancy-related lines increase in intensity with vacancy concentration.

Larger crystals show more prominent vacancy-related spectral lines.

Specific lines at 70 cm^{-1} are linked to vacancies in p-dichlorobenzene.

Abstract

Using a method Raman of spectroscopy and considering a non-uniformity of allocation of vacancies in a monocrystal, it is shown that lines with the small intensity (caused by presence of vacancies) have a major intensity in the sample of a larger size than in the sample of a smaller size. Increase of an intensity of lines at vacancy concentration increase can reveal which lines are related to presence of vacancies in the sample. For a p-dichlorobenzene, it is lines of a small intensity in a spectrum of the lattice oscillations in the field of 70 cm^{-1}.