Paschen, Friedrich

Eventually, this series of lines became known as the Balmer series. Balmer wondered whether his little formula might be extended to study the spectra of other elements. He knew similar patterns exist in the line spectra of many elements. He also wondered about spectral lines that the human eye can t see. A few years later, in 1906, additional series of lines were in fact discovered for hydrogen in the ultraviolet region of the spectrum. These were called the Lyman series after their discoverer, Theodore Lyman. Other famous series are the Paschen series, named after German scientist Friedrich Paschen, the Brackett series, named after U.S. scientist F. S. Brackett, and the wonderful Pfund series, named after U.S. scientist August Herman Pfund. The Paschen, Brackett, and Pfund series lie in the infrared region. ... 

Consequently, Friedrich Pasc hen (1804-1873) included the culminations of the moon in his water level analyses at the Wismar gauge station (Paschen, 1856) in order to prove the existence of Baltic Sea tides. His primary goal was to clearly disprove the widespread notion that the ebb and flood tides are not noticeable in the Baltic Sea. This was also supported by the observation that, with constant wind conditions, the mouths of rivers discharging into the Baltic Sea could be observed to alternate several times a day between inflow and outflow. 

For the Balmer series, nf is simply 2 and n, takes the values 3, 4, 5, or 6. In 1908 the German physicist Friedrich Paschen (1865-1947) discovered new spectral lines fitting the above equation if nf = 3 and n = 4 and n, = 5. In 1906, Harvard physicist Theodore Lyman (1874-1954) discovered an ultraviolet series of spectral lines from hydrogen corresponding to nf = 1 and some 16 years later infrared spectral lines were discovered corresponding to nf = 4 and nf = 5. 

At very high magnetic fields a splitting pattern known as the Paschen-Back effect occurs. In this pattern, named for the German spectroscopists Friedrich Paschen and Ernst Back in 1912, the basic pattern returns to that of the normal Zeeman effect, but with each line split up into a set of closely spaced lines. This occurs because the total orbital and spin angular momentum vectors of the atom, denoted L and S respectively, precess independently about the direction of the magnetic field. 

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