https://youtube.com/watch?v=JO_EHceV9sk [Embed] Identify chemicals with radio frequencies - Nuclear Quadrupole Resonance (MRI without magnets)

> How to build and test an NQR spectrometer, which is similar to MRI, but uses no magnets. NQR frequencies are unique among all tested compounds, so detecting a resonance indicates a near certainty that a specific chemical is present.