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An Alternative Strategy to Polymorph Recognition at Work: The Emblematic Case of Coronene
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posted on 2018-07-24, 00:00 authored by Tommaso Salzillo, Andrea Giunchi, Matteo Masino, Natalia Bedoya-Martı́nez, Raffaele G. Della Valle, Aldo Brillante, Alberto Girlando, Elisabetta VenutiWe
show that the development of highly accurate density functional
theory calculations coupled to low-frequency Raman spectroscopy constitutes
a valid method for polymorph characterization alternative/complementary
to X-ray. The method is applied here to the temperature-induced, first-order
phase transition of coronene, known for a long time, but has remained
structurally uncharacterized due to crystal breaking during the process.
The astonishing fidelity of the Raman calculated spectra to the experiments
allows us to unambiguously identify the low-temperature phase with
the β-coronene polymorph, recently reported as new and obtained
in the presence of a magnetic field. We also suggest that additional
measurements are needed to confirm that a magnetic field can actually
drive the growth of a β-polymorph surviving indefinitely at
ambient temperature.