July 22, 1887, in Hamburg (Germany) – October 30, 1975, in Berlin (Germany)
Gustav Ludwig Hertz began his studies at the Johanneum school (Hamburg) and later at the universities of Göttingen, Munich and Berlin until graduating in Physics in 1911. His thesis dealt with the infrared absorption of carbon dioxide in relation to pressure and pressure partial.
He obtained a position as a research assistant at the Physics Institute of the Friedrich Wilhelm University (Berlin) in 1913.
Together with another scientist, James Franck, they carried out research on the impact of electrons that led them, in 1914, to carry out their famous experiment that confirmed and supported Bohr's atomic model and opened the doors to quantum mechanics formulated by Max Planck.
Just as he was researching and quantifying the ionization potential of various gases, World War I begins and he has to go to the front lines. In 1915, he is seriously wounded.
He continues with his studies and demonstrated the quantitative relationships between the series of spectral lines and the energy loss of electrons when colliding with atoms.
In 1925, he and James Franck received the Nobel Prize in Physics for their discoveries on the passage of electrons through a gas. In addition, he received the Max Planck Medal from the German Physical Society.
He returns to Berlin with the aim of rebuilding the Physics Institute. During this time, he is the director and responsible for the discovery of a method to separate neon isotopes using a diffusion cascade.
After World War II, in 1945, he moved to the Soviet Union, where he worked as head of a research laboratory until 1954, when he rose to the position of director of the Institute of Physics at Karl Marx University in Leipzig (Germany).
In 1961, he was named Professor Emeritus and retired, living between Leipzig and Berlin.
He had two sons also physicists, Dr. Carl Hellmuth Hertz and Dr. Johannes Hertz.
Throughout his life he published many of his works, both in collaboration with Franck and individually.
He was a member of the German Academy of Sciences in Berlin, the Göttingen Academy of Sciences, the Hungarian Academy of Sciences, the Czechoslovak Academy of Sciences and a foreign member of the USSR Academy of Sciences.
How is the Franck-Hertz experiment performed?
They carried out an experiment that demonstrated the existence of discrete excited states in mercury atoms, confirming the prediction of the Bohr model (which they had postulated a year earlier) that atomic bound systems occupy only certain energy states, i.e. That is, its energy was quantized. Therefore, the corresponding energy spectrum was not continuous but discrete.
Inside a low-pressure discharge tube, where mercury vapor is present, the electrons, emitted with a known energy by a heated filament acting as a cathode, are accelerated by a voltage towards a positively charged grid, so that they are emit with a certain kinetic energy. After the grid, there was a collector plate with a small negative voltage relative to the grid, which acts as a retarding potential for the electrons. Therefore, there is a potential difference between the grid and the collector plate (called braking power). By means of an ammeter it is possible to measure the current intensity and thereby obtain quantifications of the energy levels corresponding to the atomic bound states.