Jerome Karle (1918-2013)

[Jerome Karle]

Jerome Karle, who died on June 6th of liver cancer, was born Jerome Karfunkle on June 18, 1918, in Brooklyn, the son of immigrants from Eastern Europe. A precocious product of New York public schools, he completed high school at just 15 years old and went on to the City College of New York. He graduated in 1937 along with Herbert Hauptman (they did not know each other at the time) and Arthur Kornberg, another of City College's many Nobel laureates. He obtained a master's degree in biology from Harvard and pursued graduate studies in chemistry at the U. of Michigan.

At Michigan, he met his future wife Isabella Lugoski, on the first day of a physical chemistry lab. At the U. of M, Karle studied the diffraction patterns resulting from firing electrons at gases. After completing their dissertations in 1943, they moved to the U. of Chicago to work on the Manhattan Project. In 1946, they moved to the US Naval Research Laboratory (NRL) in Washington DC, where they remained until their retirement in 2009. Initially, Jerome and Isabella continued to focus on electron-diffraction experiments. In parallel, Jerome made a theoretical analysis predicting what diffraction patterns to expect from oriented hydrocarbons, and this got him wondering about applying his theories to the analysis of crystal structures. It was around this point that the Karles were joined by Herbert Hauptman.

Starting in 1950, Karle and Hauptman drew on fundamental knowledge about the nature of matter (specifically, that one cannot have negative electron density) to find mathematical relationships among the diffracted waves. Soon after, they established a probability theory, which they brashly announced in 1953 in an abstruse monograph entitled 'Solution of the Phase Problem'.

Early reception of the Karle–Hauptman work was at best muted. Quoting Karle himself, 'during the early 1950s ... a large number of fellow scientists did not believe a word we said'. The tide was turned by Isabella when she applied the work to challenging structures such as peptides. In 1966, Isabella and Jerome Karle published a landmark paper in Acta Crystallographica, which laid out step-by-step how to determine crystal structures. Others joined the venture with computer programs, and ever increasing numbers of ever more complex structures came to be determined through direct methods.

By the time Karle and Hauptman received the Nobel prize, Karle had become prominent in crystallography circles; Jerome served as President of the IUCr in the early 1980s, and was President of the ACA in 1972. He was elected to the National Academy of Sciences in 1976.

Karle's interests were broad, as suggested by the name he gave his unit at the NRL - the Laboratory for the Structure of Matter. The work there ranged from electron diffraction of gases to quantum chemistry of excited states, to the study of glasses and amorphous materials, and of course, crystals. Although these activities engaged several group members and were largely experimental, the Jerry I knew was a lone theoretician; he authored many papers alone and his main working interaction was with a computer programmer who tested his theories.

Ultimately, Karle's major contribution was to allow researchers to shift their focus from the intricacies and challenges of crystallography to molecules and biochemical mechanisms. He turned chemical crystallographers into crystallographic chemists.

The mathematical approaches that Karle and Hauptman established, known as direct methods, have helped researchers to elucidate the structure of key molecules such as vitamins and hormones, and to gain insight into biochemical mechanisms. Karle and Hauptman shared the 1985 Nobel Prize in Chemistry for their work.

The awarding of the Nobel came as something of a surprise to Jerome. He was 39,000 feet over the ocean on a transatlantic flight when the pilot made an announcement over the loudspeaker. 'We are honored to have flying with us today America's newest Nobel Prize winner, and he doesn't even know it. In fact, the award is so new that Dr Jerome Karle, located in seat 29C, left Munich this morning before he could be notified that he was a recipient of the Nobel Prize in Chemistry'. In the cabin, he was feted with champagne.

Survivors include his wife Isabella; three daughters, chemists Louise Karle Hanson and Jean Karle, and geologist Madeleine Karle Tawney, and four grandchildren.

Adapted from Nature, 499, p. 410 (July 25, 2013) by Wayne Hendrickson, with some additions from the June 14th Washington Post article by Emily Langer