Rabi focused on during their experiments in the 1930s. The first attempts to demonstrate that nuclear spin could be flipped by an oscillating magnetic field were carried out by Dutch physicist Cornelius J. Gorter in the early 1930s. Unfortunately, Gorter wasn't able to detect spin transitions due to problems with his experimental design that caused a low signal to noise ratio. Due to this failure, Gorter is now recognized as “the man who almost discovered NMR.” It wasn't until 1937 that another physicist, Isidor Rabi, discovered that spin transitions could be induced via time varying fields. Rabi’s experimental setup involved passing a molecular beam of lithium chloride (LiCl) into a varying magnetic field (generated by changing the current through an wire), and then radiating the molecules with radio waves of constant frequency. In 1938, Radi published his experimental results. He reported that LiCl had absorbed radio waves at particularly wavelengths and dubbed this newly discovered phenomena, nuclear magnetic resonance. While Rabi is credited for discovering NMR, the very unnatural setup of Radi’s experiment meant that it didn't have much practical application for everyday materials.
In 1946, two independent research teams-one headed by Felix Bloch at Stanford University, and the other, headed by Edward Purcell at Harvard University- observed the existence of NMR in condensed matter. The first structural analysis of a sample using NMR was subsequently carried out in 1951. Both men were awarded the Nobel Prize for Physics in 1952 for their discovery. From this point, the use of NMR grew very rapidly. Initially, only 1H NMR were used due to its substantially higher sensitivity in comparison to 13C NMR. In fact, 1H NMR is approximately 104 times as sensitive compared to 13C NMR. However, with the advent of Fourier transform based NMR in 1970, the use of 13C NMR has become a vital and widespread tool for the organic chemist....