Gaja Alaga

Who was Gaja Alaga?

Gaja Alaga was a Croatian theoretical physicist who specialised in nuclear physics.

He was born in noble family of Bunjevac Croats in the village of Lemeš in northwestern Bačka in Kingdom of SHS.

He was an academician of the Croatian Academy of Sciences and Arts since 1968 and a professor at the University of Zagreb Faculty of Science. He worked in the Ruđer Bošković Institute in Zagreb, the Niels Bohr Institute in Copenhagen, the University of California, Berkeley, and Ludwig-Maximilians University in Munich.

In 1955, cooperating with Kurt Alder and Ben Roy Mottelson, Alaga discovered the K-selection rules and intensity rules for beta and gamma transitions in deformed atom nuclei. This discovery was key to the development of new nuclei models which confirmed that subatomic particles can distort the shape of the nucleus. These models challenged Aage Bohr, Ben Roy Mottelson and James Rainwater's earlier theory that the nucleus has a perfect spherical shape.

Also in 1955, the journal Physical Review published Alaga's rules for beta and gamma transitions for heavily damaged atomic orbits. Both discoveries are known as Alaga rules, and are now in everyday use among nuclear scientists and in scientific literature.