Carl H. Hermann

Carl Heinrich Hermann (17 June 1898 – 12 September 1961), or Carl Hermann, was a German physicist and crystallographer known for his research in crystallographic symmetry, nomenclature, and mathematical crystallography in N-dimensional spaces. Hermann was a pioneer in crystallographic databases and, along with Paul Peter Ewald, published the first volume of the influential Strukturbericht (Structure Report) in 1931.

Early life and education
Hermann was born in the north German port town of Wesermünde to parents both of long-time ministerial families.

He studied mathematics and physics at the University of Göttingen, where he received his doctorate in 1923, as a pupil of Max Born and a fellow student with Werner Heisenberg. Upon graduation, he moved to Berlin-Dahlem to work under Herman Francis Mark at the Kaiser Wilhelm Institute for Fiber Chemistry (now Fritz Haber Institute of the Max Planck Society). Later in 1925, he joined Paul P. Ewald at the University of Stuttgart, where he achieved his habilitation in 1931 with the thesis title Die Symmetriegruppen der amorphen und mesomorphen Phasen.

Early career
Along with Ewald in Stuttgart, he nurtured the growing field of crystallography, especially the study of space groups, and began what was later to become Structure Reports (Strukturbericht), a reference series giving every known crystal structure determination. During his Stuttgart years, Hermann also developed the first description of anisotropic properties of materials from a crystallographic perspective.

When the Nazi Party rose to power, he objected to its political restrictions on academic positions, leaving to take a position as a physicist with the industrial dye firm I.G. Farben at Ludwigshafen, where he continued his crystallographic research and studied symmetry in higher-dimensional spaces.

World War II
During World War II, he and his wife (1900 – 1997), who were both Quakers and pacifists, helped provide deported Jews with food, clothing and other resources. After the city of Mannheim was declared Judenfrei (free of Jews), they hid Jews in their home from Nazi authorities. In 1943 he and his wife were arrested and brought before a special tribunal. As his scientific work was deemed too essential to the war effort, Hermann was given a "mild" sentence of eight years of imprisonment, while Eva was sentenced to three years. He was allowed to continue his research while imprisoned, being brought to his laboratory in the mornings and taken back to his cell at night. After two years of imprisonment, he and Eva were both released at the end of the war.

Later activities
After the war, he lectured briefly at Darmstadt Polytechnic (now Darmstadt university of technology) between 1946 and 1947. Then, in 1947, he accepted a newly formed chair in crystallography at the University of Marburg, where he became director of the Crystallographic Institute and remained until his death. During his Marburg years, Hermann's research laid the foundation for N-dimensional crystallography.

Legacy
The symmetry notation introduced by Hermann and Charles-Victor Mauguin, which later became an international standard notation for crystallographic groups known as the Hermann–Mauguin notation or International notation.

In 1976, for their work in saving Jews from the Holocaust, Hermann and his wife Eva were honored as Righteous Among the Nations by Yad Vashem. Eva Hermann wrote about the honor: "I am fully conscious of the fact that my late husband and I did nothing special; we simply tried to remain human in the midst of inhumanity."

In August 1994, the German Crystallographic Society (DGK) established the Carl Hermann Medal, its highest distinction, for outstanding contributions to the science of crystallography.