Raman Scattering — FRCA Primary MCQ
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Correct answer: D — Changes in wavelength of scattered light characteristic of each molecule
In Raman scattering monochromatic laser light interacts with gas molecules. A small fraction of scattered photons undergoes a wavelength shift (Raman shift) that is characteristic of the molecular bonds. This allows identification and measurement of all respiratory gases including N2 and O2 (which cannot be measured by infrared absorption). Fast response time.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment