The Raman spectrum and phase transition in sym-triazine

G. R. Elliott, Zafar Iqbal

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


The complete Raman spectrum of polycrystalline sym-triazine has been observed at different low temperatures. The Raman active molecular vibrations have been assigned on the basis of the published normal coordinate analysis of the free molecule, while the external Raman active vibrations at 293°K have been assigned in terms of molecular librations and translations, based on a model lattice calculation of frequencies and Raman intensities. Accurate temperature dependent Raman measurements of the splitting of the internal mode at 1550 cm-1 coupled with differential thermal calorimetric observations confirm the existence of a phase transition of second order character at T0 = 196 ± 1°K. The transition proceeds continuously below T0 as shown by sizable shifts of certain phonon frequencies with temperature. The temperature dependences are consistent with the transition displacements proposed by Coppens and Sabine, but do not show the existence of a soft Cochran type phonon.

Original languageEnglish (US)
Pages (from-to)1914-1918
Number of pages5
JournalThe Journal of Chemical Physics
Issue number5
StatePublished - 1975
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


Dive into the research topics of 'The Raman spectrum and phase transition in sym-triazine'. Together they form a unique fingerprint.

Cite this