A Pioneer of Israeli Science

Few scientists get the chance of becoming both dedicated researchers and influential leaders during their lifetime, serving as an inspiration to many in the scientific community with a list of achievements that includes not only scientific findings, but also the very shaping of the scientific capabilities, values, standards, principles, and reputation of a young state.

Chaim Weizmann was such a leader, turning his scientific and educational endeavors into a cornerstone of Zionism, and inspiring the hearts of many to rally behind the cause of Israel’s independence through scientific research. After his passing in 1952, his legacy continued to attract eminent scientists to align their destinies with the State of Israel. Among these, one figure who stands out prominently is Joshua Jortner, who recently celebrated his 90th birthday.

Scientist, Theoretician, and Leader. Yehoshua Jortner | Illustration: Michal Barkai

A Common Language

Jortner was born in Tarnów, Poland, on March 14, 1933 – exactly 54 years after Albert Einstein. Before delving into scientific research, however, he acquired, by force of circumstance, proficiency in several languages that would prove invaluable in his future endeavors. His parents named him Joshua, after his grandfather.

In the summer of 1939, his father Arthur enrolled him in the local Jewish school Safa Breura (“Clear Language”). Young Joshua managed to visit the school with his mother Regina, but on the day he was supposed to start first grade, September 1, 1939, the Nazis invaded Poland and WWII broke out. The parents, who owned a textile factory, and their two children Joshua and Lily, fled to Czernowitz, Romania (today, Chernivtsi, Ukraine). Joshua, who spoke Polish, began studying German with a private tutor, and later also learned Romanian.  

As Czernowitz was too close to the border, the Jortners decided to move to the Romanian capital Bucharest, fearing for their future. There, Joshua finally began attending school on a regular basis. As the language of instruction was French, he had to master it as well.

Several months later, Arthur Jortner broke the exciting news that there was a chance to immigrate to Palestine soon. Young Joshua needed to learn Hebrew – and a private tutor was hired for this purpose. Indeed, on November 13, 1940, the family arrived in Israel, and seven-year-old Joshua had already become proficient in five languages.

"Family name:Jortner" - Immigration Record from the Jewish Agency, November 1940. Source: Taboola.

A Makeshift Homemade Lab

The family settled in Tel Aviv. Joshua began attending the Tel Nordau elementary school, before proceeding to the Ironi Aleph High School. It was there that his passion for science and chemistry in particular, was nurtured, thanks to teachers with rich research and academic experience. The enthusiastic Jortner, along with some friends, established a chemistry club and even built an improvised home laboratory. One of the experiments they conducted nearly set his parents’ house on fire. Three of the club members would later become chemistry professors: Assa Lifshitz at the Hebrew University, Raoul Kopelman at the University of Michigan, and Jortner himself. 

At 18, he began studying chemistry at the Hebrew University of Jerusalem, as part of the IDF Academic Reserve program, after pondering the possibility of choosing between chemistry and history, a discipline that would remain close to his heart throughout his life. One of his classmates was Ruth Erez (née Rosenberg), who would later become Prof. Ruth Arnon. In 1955, he completed his master's degree and went on to pursue a doctorate in physical chemistry, focusing on the photochemistry of solutions, specifically on the way ions surrounded by water, particularly metal ions, respond to light. His supervisor was Gabriel Stein – one of the founding fathers of Israeli chemistry. Jortner also studied theoretical physics with Giulio (Yoel) Racah. Concurrently and in parallel to these endeavors, he served for four years as an officer in the IDF Science Corps.

Upon concluding his doctoral studies in 1960, Jortner joined the Hebrew University as a lecturer. Shortly thereafter, however, he relocated to the US for post-doctoral training. His supervisor there, Stuart A. Rice from the University of Chicago, later a Wolf Prize laureate (2011), was one of the leading theoretical chemists of the 20th century.

In a conversation with the Davidson Institute website, Rice referred to things he wrote for Jortner’s 70th birthday - who has become his close friend: “Joshua arrived in Chicago in the early winter of 1962. From the very first day, a collegial relationship was formed between us, characterized by frequent discussions covering a very broad array of interesting problems, accompanied by almost frenetic activity that included flights of imagination mixed with detailed analytical and technical calculations, and great productivity. […] Joshua […] has become a statesman for science worldwide, not just science in Israel. He is recognized internationally both for the quality of his contributions to science, and for his evocative representation of the potential good that science generates”.

Yuval Ne'eman, 1966. Productive Collaboration | Photo: Science Photo Library"

Global Status

Jortner returned to Israel in 1964. Soon thereafter, George Weiss, the first president of the newly established Tel Aviv University, persuaded him to join the young university’s faculty and establish its chemistry department. In this capacity, he productively collaborated with Yuval Ne’eman, the head of the Physics Department. The two continued to work closely in the subsequent years, during which Ne’eman became the president of the university and Jortner served as vice-president.

Those years at the university were intense. Jortner devoted most of his daytime hours to the university’s ongoing management, and devoted his nights to research. This left him very little time to dedicate to his wife Ruth, a cardiologist (now retired), and to their children Roni and Iris.

Throughout fifty years of research, Jortner made multiple and varied contributions to the field of physical chemistry. Among other things, he studied the theory of hydrated electrons, electron transfer processes in solvents and in biophysical systems, the dynamics of over-refrigerated large molecules, and much more. Many of these contributions were sufficient to earn him international recognition, but the field in which he gained worldwide fame was the study of the dissipation of energy in molecules.

In 1968, together with his department colleague Mordechai Bixon, Jortner published the paper “Intramolecular Radiationless Transitions”. The paper, which became a cornerstone in the study of chemical dynamics, and has been cited in approximately 1,500 scientific publications, describes and explains the interactions between light particles – photons – and molecules, and the conversion of photonic energy into nuclear kinetic energy. This energy propels a wide range of important processes in chemical and biological systems in nature. Bixon and Jortner’s theoretical predictions were confirmed nearly twenty years later, when Egyptian-American chemist Ahmed Zewail developed the first ultrafast lasers.

In half a century of research, Jortner made multiple and varied contributions to the study of physical chemistry. Among other things, he studied the theory of hydrated ions, electron transfers in solvents and biophysical systems, the dynamics of over-refrigerated large molecules, and much more. Many of these contributions have been sufficient in themselves to win him international renown, but the area that won him true global fame was the study of energy transitions in molecules.

In 1968, together with his department colleague Mordechai Bixon, Jortner published “Intramolecular Radiationless Transition”. The article, which became a cornerstone in the study of chemical dynamics, and cited since in 1,500 scientific publications, describes and explains the encounter between light particles – photons – and molecules, and the conversion of photonic energy into nuclear motion energy. This energy propels a long range of important processes in natural chemical and biological systems. Bixon and Jortner’s theoretical predictions were confirmed nearly twenty years later, when Egyptian-American chemist Ahmed Zewail developed the first ultrafast lasers.

Jortner’s scientific endeavors were highly varied. When he was awarded the EMET Prize in 2008, the prize committee noted that “his original and unique projects […] have shaped many areas of physical chemistry, particularly in the study of molecular relaxation, electron transfer processes, photo-selective chemistry, and the chemistry of molecular clusters''.

This extensive list deserves elaboration. In physics and chemistry, relaxation processes in physics and chemistry occur when something disrupts the equilibrium in a certain system, which then begins to revert to equilibrium; equilibrium, in this context, means a condition in which no spontaneous changes occur in the system’s internal structure, no external forces act upon it, and no heat is exchanged between it and its environment. The molecular relaxation studied by Jortner occurs when molecules encounter a sudden burst of light, and seek to return to their calm and balanced pre-disturbance state. Jortner was interested in this process, specifically in condensed matter systems, such as liquids and solids, which exist in biophysical systems among others.

Jortner began studying photochemistry already during his doctoral work, and continued to focus on it later on. This field deals with chemical reactions activated by light, such as the processes that occur in the light receptors in our eyes, and the green receptors that enable plants to convert light into chemical industry. Some of the engineering applications of photochemistry are also familiar to us all – non-digital photography, printed circuits, etc. The photoselective chemistry studied by Jortner involves reactions that are selectively affected by the interactions between molecules and light. He also co-edited a comprehensive book on this subject, together with his colleagues Raphael (Rafi) Levine and Stuart Rice.

News from the newspaper 'Chadashot' about Jortner and Levine winning the Wolf Prize, January 1988.

Impressive Scientific Output

 

Jortner’s scientific productivity is exceptional, even relative to the long decades he spent as a researcher. Over the years, he has authored and co-authored more than 270 scientific papers, and co-edited 28 books. He also supervised fifty doctoral students and dozens of postdoctoral fellows.

Many of the senior researchers at the Tel Aviv University School of Chemistry were among Jortner’s doctoral students. The list includes Israel Prize laureates Abraham Nitzan and Yossi Klafter, both known for his work in chemical dynamics; spectroscopists Dan Huppert and Ori Cheshnovsky; magnetic resonance expert Gil Navon and molecular beams researcher Uzi Even. Theoretician Uzi Kaldor also was his graduate student. It would be no exaggeration to say that the majority of theoretical chemists currently active in Israel, and many of the Israeli physical chemists and chemical physicists, have started out under the supervision of Joshua Jortner, his Hebrew University colleague Rafi Levine, or their many students.

Jortner’s achievements were duly recognized. He was awarded the Israel Prize for chemistry before the age of 50 – a remarkable achievement. In addition, he was the recipient of the Weizmann Prize, the Rothschild Prize, the EMET Prize, and the most prestigious Wolf Prize, which he shared with Levine in 1988. His contributions were further acknowledged with honorary doctorates from seven universities worldwide, and he was selected as an honorary member by fourteen academies of science. In the late 1990s, shortly before his retirement, he even served as President of the International Union of Pure and Applied Chemistry (IUPAC). 

Signature of Prof. Joshua Jortner. Source: Israel State Archives

The Cutting Edge of Scientific Quality

In 1986, Jortner was appointed the sixth president of the Israeli National Academy of Sciences. It was an expected appointment, given his extensive administrative experience and senior status in the global discipline of physical chemistry. He served in this role for nearly a decade, during which time he also served as scientific advisor to three prime ministers – Shimon Peres, Yitzhak Shamir, and Yitzhak Rabin. The willingness of decision-makers to heed his counsel allowed him to make significant contributions to strengthening Israel’s position in qualitative scientific and technological advancement.

 

“The State of Israel is unique in terms of the central role science plays in it”, Jortner articulated his worldview on the eve of receiving the EMET Prize. “An American scientist needs only worry about America’s scientific level. An Israeli scientist must contribute to scientific education, since the State of Israel is dependent on our qualitative edge”.

 

At the request of Prime Minister Peres, Jortner prepared a master plan for establishing a national grant foundation to support basic research in Israeli academia. This gave rise to the founding of the Israel Science Foundation (ISF), which distributes generous grants to hundreds of Israeli scientists annually, based on a thorough professional evaluation of their research.

 

In 2014, the Israel Academy of Sciences held a symposium to mark Jortner’s 80th birthday. Surrounded by family members, friends and numerous students, Jortner listened as speakers paid respect for his scientific career, for being the academy’s ambassador in state institutions, and the state’s ambassador in the academic community. 

 

His former student Yossi Klafter, who was at that time the president of the Tel Aviv University, concluded:

 

“We often speak of Israel as the “startup nation”, with high-level academic institutions and researchers. These things were not created out of thin air… Joshua was one of those who laid the foundations. I think of Joshua as someone who has set standards for excellence, and provided a personal example for maximal dedication to science, not only in his own field, but to science in the State of Israel as a whole. He has a huge impact on those around him, and to this day, there’s a bit of Joshua in each and every one of us.

Over the past decade, Jortner published only a few papers, and naturally, his public appearances have become rarer with age. He recently celebrated his 90th birthday, and as in every year, Tel Aviv University held the annual chemistry lecture in his honor. In the name of the entire scientific community in Israel, we wish him good health and a long life