Temperature-Dependent Raman: a Peak that Moves

A Raman spectrometer reads a material’s vibrations. Heat or cool the sample on a stage and the peak shifts and broadens — an optical fingerprint of temperature. Drag the slider through the range of a heating/cooling stage.

25 °C
Interactive Raman spectrum showing a single optical-phonon peak. As temperature rises the peak softens to lower wavenumber and broadens, while cooling sharpens it and shifts it higher — the anharmonic temperature dependence used to read temperature, strain and phase from a spectrum.
Temperature
25 °C
Peak position
1580 cm⁻¹
Linewidth (FWHM)
14 cm⁻¹
The physics. Raising temperature expands the lattice and shortens the phonon lifetime through phonon–phonon (anharmonic) scattering, so the mode softens (lower frequency) and broadens (larger linewidth). For the graphene G band near 1580 cm⁻¹ the measured shift is about −0.016 cm⁻¹ per °C, giving a clean, calibratable thermometer in the spectrum.