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The start of our story is bound up initially with the discovery of the electron, subsequently with the mysteries of quantum theory together with observations about atomic spectra. |
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| 1823 | André-Marie Ampére - associated magnetism with the motion of electric charge. |
| 1834 | Michael Faraday's experiments on electrolytes. |
| 1891 | George Johnstone Stoney "names" the electron. |
| 1897 | J.J.Thompson measures e/m for the electron. |
| 1900 | Joseph Larmor published his collected papers on electromagnetism in 1900 in his book "Aether and Matter". |
| 1921 | Stern and Gerlach's experiment. |
| 1924 | Louis de Broglie proposed that had both wave and particle properties. |
| 1925 | Pauli's Exclusion Principle |
| 1925 | Samuel Goudsmit and George Uhlenbeck discovered electron spin |
| 1928 | Paul Dirac showed that the spin quantum number appears automatically if a relativistic Hamiltonian is used for the wave equation. |
| After 1925 there were numerous related measurements and theoretical developments, - molecular beam experiments, also resonant molecular beam experiments, the prediction of resonant absorption, microwave measurements on small molecules, and spin lattice relaxation measurements. Then in World War II high power microwave generators (magnetrons) and low power microwave oscillators (klystrons) and other electronics were developed for use with Radar. After the war these devices were incorporated in early EMR spectrometers. However there were a number of important observations before the first resonance experiments, in particular three still impinge strongly on modern EMR experiemnts. The Kramers theorem, the Breit Rabi formulae and early experiments on spin lattice relaxation. Hovering behind all of this is the figure of Paul Dirac. | |
| 1930 | The Kramers Theorem. |
| 1931 | The Breit Rabi formulae |
| 1932 | Spin Lattice Relaxation. |
| 1939 | Rabi and associates - first experimental observation of magnetic resonance |
| 1944 | Evgeny Zavoisky - first measurement of Electron Paramagnetic Resonance in Kazan State University. |
| 1946 | Felix Bloch's famous equations - Physical Review, 1946, 70, 460. |
| 1946 | First electron resonance measurements of gases by R.Beringer and co-workers |
| 1952 | ODMR - optically detected magnetic resonance |
| 1956 | ENDOR measured by George Feher |
| 1966 | Ernst and Anderson's specification for FT-PMR |
| 1974 | Yacob Lebedev - first VHF EPR experiments |
| 1974 | First NMR imaging experiments. See also EMRF online |
| 1980 | Röder's FT-PMR machine |
| 1986 | Jack Freed's's first FT and 2D EPR Experiments |
| 1994 | Jorg Wrachtrup, Jurgen Kohler, E.J.J. Groenen and Christian von Borzyskowski carry out the first single molecule EPR experiment. |