High-pressure effects in pyrene crystals: Vibrational spectroscopy

B. Sun, Z. A. Dreger, Y. M. Gupta

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The response of pyrene crystals to high pressure was examined using Raman and FTIR spectroscopies. Raman spectra of external and internal modes were measured up to 11 GPa. Changes in the external modes were observed at ∼0.3 GPa, indicating the onset of a phase transition. We demonstrated that at this pressure pyrene I (P21/a, 4 mol/unit cell) transforms to pyrene III (P21/a, 2 mol/unit cell). Further increase of pressure produced a gradual broadening of the internal modes and an increase of fluorescence background, indicating the formation of another phase above 2.0 GPa. Irreversible chemical changes were observed upon gradual compression to 40 GPa. FTIR spectroscopy of the recovered product indicated a transformation of pyrene into an amorphous hydrogenated carbon (a-C:H) structure.

Original languageEnglish
Pages (from-to)10546-10551
Number of pages6
JournalJournal of Physical Chemistry A
Volume112
Issue number42
DOIs
StatePublished - Oct 23 2008

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