Crystal Field Splitting in Raman Spectra of Polytetrafluoroethylene

Abstract
Crystal field splitting of Raman‐active line group fundamentals has been observed for the crystalline phase of polytetrafluoroethylene found at temperature below 19°C. At − 180°C Raman lines near 575 and 1215 cm−1 are split into components separated by 3.5 and 4.4 cm−1, respectively. Splitting of the Raman line near 385 cm−1 increases from 5.2 cm−1 at 0°C to 6.4 cm−1 at − 180°C, indicating increasing intermolecular interaction with decreasing temperature. It is suggested that the space group of this phase is P2 1 and that the unit cell has dimensions a = 5.59 Å, b = 9.76 Å, c = 16.88 Å with β = 90° and contains two molecules.