vibrational spectroscopy infrared absorption spectroscopy infra-red spectrophotometry Infrared absorption spectroscopy is a type of vibrational spectroscopy where the sample absorbs radiation from the infrared region. [CHMO] infra-red absorption spectroscopy IR spectrometry infrared absorption spectrometry IR absorption spectrometry IR infra-red absorption spectrometry infra-red spectrometry IR spectrophotometry IR spectroscopy infrared spectroscopy infrared spectrophotometry IR absorption spectroscopy infrared spectrometry infrared (IR) spectroscopy infrared absorption spectroscopy