Radiofrequency radiation energy

The energy of nuclear spin states is split in an externally applied magnetic field. The absorption of radiofrequency radiation can cause transitions between these two states. 

Non -ionizing Radiation - Radiation that has insufficient energy to remove electrons from atoms. Laser and Radiofrequency radiation is considered non-ionizing radiation. 

Nuclear magnetic resonance NMR Quantized orientation of nuclear spin in a magnetic field. Energy separations sampled with radiofrequency radiation. Identification of histidine by deuterium exchange (N—H vs. N—D) at or near metal, especially if paramagnetic. 

Radiofrequency radiation induces up or down spin flips with equal probability. The number of quanta exchanged between the spins and the RF coil is enormous. Consequently, the overall behavior of the system is statistical and can be described classically. Energy is absorbed by the spins provided there is an excess population in the lower state at the time the RF is applied. This spin energy change is far too... 

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