Polyethylene’s Temperature Dependent Terahertz Spectrum

The terahertz spectra of polyethylene have been observed over a wide temperature range, 6-300 K. A prominent mode has been identified and characterised at 79.6 cm
^-1
at 6 K. Strong redshifting of 6.2 cm
^-1
and broadening is observed upon heating to 300 K. A weak secondary mode was also observed at 6 K, but this mode quickly disappears as temperature increases. The intensity of the 79.6 cm
^-1
mode is also observed to decrease dramatically upon heating from 6–300 K, reducing to two-fifths of its original intensity. The spectrum at all other terahertz frequencies is approximately temperature independent.