Young Boris Belousov
Anatol Zhabotinsky lecturing in Pushchino
Source: Both images courtesy of Simon Shnol, Pushchino, Russia.
Boris P. Belousov (1893–1970) and Anatol M. Zhabotinsky (1938–2008) gave their names to the Belousov-Zabotinsky oscillating reactions, which the Nobel laureate Ilya Prigogine considered to be one of the most important discoveries in the twentieth century. The military and medicinal chemist Belousov was the original discoverer, and the biophysicist Zhabotinsky worked out its theory and made the reactions known. The two lived in Moscow, a few kilometers apart, and talked over the phone but never met in person.
In 1980, they shared the prestigious Lenin Prize with three other researchers; for Belousov, it was a posthumous award. Zhabotinsky moved to the United States in 1991 and spent the rest of his life in Waltham, Massachusetts, working in an untenured position at Brandeis University. After the Lenin Prize, he never won any significant award, but he is considered to be the father of a whole area of modern science, called nonlinear chemical dynamics.
Oscillating reactions* belong to the larger group of phenomena described as “nonlinear chemical dynamics.” In oscillating reactions, there are periodic changes in the concentrations of the reaction components. In those where concentration changes are manifested as color changes, the phenomenon is visually stunning. “Nonlinear chemical dynamics” may sound formidable, but deconstructing the expression shows that it is not so at all. It is about chemical reactions in which the changes of various properties may not have a simple proportional relationship (accordingly, their relationship is “nonlinear”), and the event is examined as it evolves in time (the word “dynamics” refers to this feature).
Boris Pavlovich Belousov was an obscure Soviet military and medicinal chemist and Anatol Markovich Zhabotinsky was a graduate of Moscow State University who then worked in various research institutes in and near the Soviet capital. Belousov died in Moscow and Zhabotinsky in Waltham, Massachusetts. Except for the prestigious Soviet award, the Lenin Prize, which they shared with three others, no other recognition came their way. Belousov did not live to enjoy the Lenin Prize; by the time it was announced, he had been dead for ten years. Neither Belousov nor Zhabotinsky was elected to the Soviet Academy of Sciences. Their fame is due to the fame of the reactions named after them, the Belousov-Zhabotinsky reactions. Neither seems to have taken a prominent place in the annals of science. This is why I am referring to the late Ilya Prigogine, the Russian-born Belgian Nobel laureate, to place Belousov’s discovery and Zhabotinsky’s follow-up work in proper perspective.
Prigogine was born in Moscow just a few months before the communist revolution and died in Brussels as a Belgian viscount. His father was a factory owner and chemical engineer, and his mother, a former student of the Moscow Conservatory of Music. The family left the Soviet Union in 1921 and settled in Belgium. Prigogine had a distinguished career and became one of the most decorated scientists of all time. I met him for the first time in 1969, in Austin, Texas. There, at the University of Texas, a center was named after him and he spent a part of his time there annually. We were both visiting the chairman of the physics department at his lake house for a weekend. I was a research associate at the department. Prigogine was not yet a Nobel laureate but he was already Prigogine—his name already had an aura about it of one who was making great contributions to science.
He received his unshared Nobel distinction in chemistry in 1977 for his contributions to nonequilibrium thermodynamics.1 Thermodynamics is about the movement of heat, and since all systems move toward equilibrium, the state of equilibrium used to be almost exclusively the focus of attention of researchers. Prigogine was among those pioneers who recognized the special importance of learning about nonequilibrium states. To illustrate their importance: living organisms are highly organized systems that are not in equilibrium; they are only moving toward equilibrium through irreversible changes.
When Zhabotinsky died, his colleague at Brandeis University Irving R. Epstein published his obituary in the prestigious British magazine Nature. He stated that Ilya Prigogine “regarded the BZ [Belousov-Zhabotinsky] reaction as the most important scientific discovery of the twentieth century, surpassing quantum theory and relativity.”2 This sounded like an exaggeration and there was no source given for this statement, but Prigogine seems to have represented this view consistently. Years before, in 1995, I recorded a conversation with Prigogine, and he being a great authority in the field, I asked him, “How important was the discovery of the Belousov-Zhabotinsky reactions?” His response was less extreme than the one referred to in the obituary, but the claim was still quite substantial:3
I think it was one of the most important discoveries of the century. It was as important as the discovery of quarks or the introduction of black holes. The significance of the Belousov-Zhabotinsky reactions is in demonstrating a completely new type of coherence. It shows that in non-equilibrium, coherence may extend over macroscopic distances in agreement with our theoretical results I mentioned. Again, at equilibrium coherence extends over molecular distances while in the Belousov-Zhabotinsky reactions this coherence extends over macroscopic distances, of the order of centimeters. This is a striking example of non-equilibrium structures.
Belousov’s story goes back to czarist times, and we know about it from the Soviet-Russian biochemist Simon Shnol, who narrated it in a double capacity. Shnol was personally involved in the story of the Belousov-Zhabotinsky reaction. Lately, he has become a science historian who has taken it upon himself to preserve and disseminate information about—as he labeled them—the heroes, villains, and conformists of Russian science.4
Ilya Prigogine in 1998 in Austin, Texas.
Source: Photograph by and courtesy of Vladimir Mastryukov, Austin, Texas.
The Belousov-Zhabotinsky reactions signify a whole class of chemical events; they are oscillating reactions in that their properties change periodically, and when the changes are accompanied by color changes, they present visually profound phenomena. For years, the reviewers and editors at Soviet journals declined to accept Belousov’s discovery.
Of course, what Belousov found did not happen without antecedents. As early as the end of the seventeenth century, the famous Robert Boyle observed flashes of luminescence when studying the oxidation of phosphorus. In the nineteenth century, Boyle’s observations were confirmed. The great time gap shows how slowly things moved back then; but there were no incentives to enhance the interest in such studies. The oxidation of phosphorus was a heterogeneous process; it involved solid phosphorus and gaseous oxygen. It happens that this very reaction is discussed in two other chapters in this book (see chapters 8 and 9).
In the beginning of the twentieth century, further heterogeneous reactions were described.5 Attempts also began to understand these oscillations and to describe their mechanism. However, they were still too complicated for scientists to grasp their essence. One of the main findings of the thermodynamic research of these processes was a negative one, that is, that it is impossible to have oscillations in the vicinity of the thermodynamic equilibrium state.
The first description of an oscillating reaction in the liquid phase—that is, in a homogeneous reaction—was described in the early 1920s. However, rather than welcoming it and launching further investigations, the chemistry community found it suspect. It was suggested that the oscillations were caused by some heterogeneous impurities. This remained the attitude of chemists toward such phenomena through the mid-1960s. The German physical chemist Karl F. Bonhoeffer tried to convince his chemistry colleagues about the possibility of oscillating reactions in solution, but in vain. A heterogeneous system is indeed easier to imagine yielding oscillating properties, whereas the causes of oscillations may remain hidden in a homogeneous system, such as a solution. In the extreme, mechanical oscillations, like a swinging pendulum, are the easiest to understand.
A periodic color change of a solution is not accompanied by any visible movement in space, and this makes it hard to accept even when one sees it with the naked eye. In addition, there were thermodynamic arguments for rejecting the idea of oscillations in solutions. There was a substantial crack in this conservative edifice when in the mid-1950s Prigogine and one of his associates published in an obscure journal two papers about oscillations far from thermodynamic equilibrium.6
Under normal circumstances, after the Soviet chemistry journals rejected Belousov’s manuscripts about his discovery of an oscillating reaction in solution, he might have turned to other publications. For example, he could have sent his manuscript to physics periodicals, which he did not consider. Yet more straightforward might have been to send out his manuscript to international journals, but this was not a possibility for Belousov at that time in the Soviet Union. It was certainly not for his lack of ability to produce his manuscript in a foreign language. He spoke very good German and French. In any case, his possibilities were severely limited because he made his discovery during one of the darkest periods of Soviet life, the last years of Stalin’s reign, in the late 1940s and early 1950s.
The sad fate of Belousov’s discovery during his lifetime tragically befitted his reclusive persona. He was born in czarist Russia into a family of a bank clerk; the family had six sons. The fate of the family was to a great extent determined by the revolutionary activities of some of the sons, and part of the family, including Boris, found themselves in exile in Switzerland. There was at that time a community of Russian exiles and political immigrants waiting for the opportunity to return to a revolutionary Russia. Legend has it that in Zurich the young Belousov met the most famous Russian exile, Vladimir Lenin, and played chess with him.
Belousov received most of his education in Switzerland at the Swiss Federal Institute of Technology in Zurich (Eidgenossische Technische Hochschule, ETH, Zürich). He became a chemical engineer, alas without an official certificate. He returned to the Soviet Union, and for a long time the lack of such papers did not matter. Eventually, he was appointed to be in charge of a big laboratory. Later, due to his inability to prove his qualifications, his position was degraded without diminishing his responsibilities. He was engaged in industrial chemistry and, increasingly, in defense-related military research. Another legend says that when he was removed from his high position, but continued the same work, Iosif Stalin personally ordered that he receive remuneration corresponding to his previous position. There is realistic foundation to such a story in that Stalin was known to make personal decisions and to micromanage segments of Soviet life, down to the minutest details.
The areas of Belousov’s scientific activities encompassed mostly gaseous chemistry and analytical chemistry; he also investigated poisonous materials. When in the mid-1930s he left his military job, he found employment in a secret medicinal institute where he dealt with substances that could be used for protection from radiation. Throughout his professional career, all his activities were classified; hence there were no publications on which his name could be found.
Belousov survived the purges of Stalin’s terror in 1937–1938, but many of his friends and colleagues did not. When two decades later, first Shnol and then Zhabotinsky wanted to involve him in their work and meet with him, he consistently declined. He said that he had lost his friends and did not want to make new friends. Belousov asked them not to bother him again about personal meetings or about including him in joint publications, but he offered his assistance and indeed proved to be very helpful. He also revealed that the idea for his oscillating reaction came out from his efforts to build some cyclic reactions, in a way analogous to the Krebs cycle of biochemical reactions, but much simpler.7 The Krebs cycle involves citric acid and Belousov’s recipe also involved citric acid. It was a simple recipe and was modified over the years, but it essentially remained as he had first communicated it. For example, Belousov used flasks and test tubes, whereas later, it was more convenient to use a Petri dish for conducting the reaction.
Here is the list of ingredients in Belousov’s recipe: a solution of KBrO3, citric acid, and sulfuric acid; and the solution contained cerium ions. The reaction showed an astonishing effect. First the liquid was yellow, then colorless, then yellow again, continuously alternating. When Belousov first observed the bands of changing color in another, similar reaction, he called his flask a “zebra.”8 This was Belousov’s discovery. He duly described his observation in a manuscript and submitted it to serious chemistry journals, such as Zhurnal obshchei khimii (Journal of General Chemistry) and Kinetika i kataliz (Kinetics and Catalysis). He made two series of attempts, the first in 1951 and the second in 1955. On both occasions, he received unpleasant responses declining publication and expressing disbelief. According to the teachings of thermodynamics, such a system in equilibrium could not have shown the effect he observed and described. It could have been considered to be a certain kind of perpetuum mobile that—we all know—cannot exist. Based on equilibrium thermodynamics, indeed, such a system was impossible. What he did not know, and what the editors and reviewers could not fathom at that time, was that the system displaying this peculiar behavior was far from equilibrium.
The journals should have checked whether or not Belousov’s observations were valid and then worried about the explanation, but nobody bothered. Later, Zhabotinsky joked to me that it was a pity that the chemists knew their thermodynamics well and so were unable to accept the report about the oscillating reaction. Later, Zhabotinsky found no difficulty in getting his papers about oscillating reactions published in biology journals, because the biologists were not versed in thermodynamics. The truth is that the chemists who had to decide about Belousov’s manuscript were limited in their knowledge of thermodynamics. What they had learned about thermodynamics at that time did not include the characterization of systems far from equilibrium. Nonetheless, they should have been willing at least to look at Belousov’s reaction; of course, this is easy to say in hindsight.
Belousov did not attempt to prove his claim, even though he could have just taken his dishes and chemicals to the editorial office and demonstrated his experiment. The editors and reviewers might have not believed their own eyes but at least should have felt uncomfortable and puzzled. Instead, Belousov just left things alone. When Shnol later urged him to get at least something about his reaction printed, he wrote up a brief manuscript and had it included in a volume of conference abstracts compiled in the Institute of Medicinal Radiation where he worked at that time. It became his only printed communication ever.9
Had Belousov been left alone, his name and discovery might have disappeared into oblivion. However, there were changes in Soviet science that impacted him and his reaction. After Stalin’s death, during the second half of the 1950s, Lysenko and his unscientific terror of biology continued. Now, instead of Stalin, Lysenko found another great protector for his unscientific views in the new Soviet leader, Nikita Khrushchev, who badly wanted to see Soviet agricultural production enhanced and wanted it to happen quickly. He was willing to believe in the miracles Lysenko promised rather than make the necessary changes in the system. Leading Soviet physicists, such as Igor Tamm, and others, were getting increasingly tired of Lysenko’s reign and damaging activities. They would have found it difficult to directly interfere in what was happening in Soviet biology, but they could introduce some initiatives in their own field concerning biology. They organized seminars on modern biology in physical research institutes, and, in 1958, they decided to create a chair of biophysics at the Faculty of Physics of Moscow State University.
The rector of the university at the time, the internationally renowned mathematician I. G. Petrovskii, supported the initiative and appointed Lev Blumenfeld to be the head of biophysics. Blumenfeld was a physicist interested in biochemistry. His father was killed in the 1937–1938 purges of Stalin’s terror. Blumenfeld was fired from his jobs more than once, the last time as a “cosmopolite” in the anti-Semitic actions during Stalin’s last years. Nikolai Semenov invited him to be in charge of a laboratory in his Institute of Chemical Physics. This was followed by the university appointment, where he made a lasting contribution by developing his department into a significant scientific center.
Blumenfeld invited Shnol to give a course in biochemistry, and Shnol now had the opportunity to involve students, including doctoral students, in conducting research in projects that had previously been neglected. Shnol received Belousov’s recipe through Belousov’s grand-nephew; then, together with his students, reproduced Belousov’s reaction. In 1961, Tamm came for a visit, and he was much taken by the demonstration of Belousov’s oscillating reaction, which two of Shnol’s students had put together. Tamm opined that it would take a long time and a lot of effort to understand the phenomenon. This was where one of the first graduates of the new department, Anatol Zhabotinsky, excelled. But it did not happen right away, only following a detour in his career.
Anatol Markovich Zhabotinsky was born in 1938 in Moscow into a Jewish family of intellectuals. Both his parents were physicists, graduates of the Faculty of Physics, Moscow State University. His father, Mark Zhabotinsky, had studied under Mikhail Leontovich, another of the great Soviet physicists, who also participated in the movement to free Soviet science from Lysenko’s charlatanism. Mark Zhabotinsky worked at the Physical Institute of the Academy of Sciences (FIAN). Anatol’s mother, Anna Livanova, specialized in the history of physics and authored books about it.
Anatol’s first love in his youth was biology, but he wanted to avoid getting into a science where Lysenko reigned. The new biophysics at Moscow State University was a godsend. It did not exist in 1955, when he started his university studies, but was already being created by 1958, when he had to choose his specialization. Several of his fellow students were the children of influential members of the Soviet Academy of Sciences or of Soviet politicians, including the son of Georgii Malenkov, who had been the prime minister between 1953 and 1955 and who, even after being demoted from that position, remained a member of the supreme leadership of the country—of the Politburo—until 1957. By then, the idea of biophysics had taken root at Moscow State University. Besides, Malenkov’s son was not the only student working to further modernization. It was a rare phenomenon in Soviet society that demands from below—in this case from students—had any impact on what was happening at all.
When Zhabotinsky, still an undergraduate in 1958, joined the biophysics department, he became Shnol’s student. Zhabotinsky was to be one of the first students to graduate from this newly organized department. Thus, his presence in Shnol’s group was equally memorable for both. According to Shnol, young Zhabotinsky was a “typical product of the [Soviet] intellectual world.”10 In this world, “the children from very early age were taught to deliberate about their environment. They loved mathematics, and during family meals they were engaged in solving puzzles and paradoxes.” Shnol saw great value in these children but found that “they could be quite unbearable. When they find themselves in normal society and experience how ignorant their peers can be, they tend to consider themselves geniuses. They think that their superior knowledge was of their own making, whereas it stemmed from their families and the favorable circumstances of their childhood.” Shnol found that this description fit his new student, Anatol Zhabotinsky, well.11
At the Faculty of Physics of Moscow State University, Zhabotinsky had a great opportunity to acquire experience in scientific research. Another great attraction was the summer field trips, including one to the field laboratory of the famous biologist Nikolai Timofeev-Resovsky. There, the students could attend brilliant lectures on genetics and theoretical biology, still taboo in most of contemporary Soviet biology. Timofeev-Resovsky was a world-class scientist, knew many famous biologists, and was a colorful personality and terrific storyteller.
Zhabotinsky’s choice for Diploma work (master’s thesis) was unusual. The biophysics department wanted to build its own electron-paramagnetic-resonance (EPR) apparatus to study the electronic structure of substances. Blumenfeld intended to form a team for the task when Zhabotinsky volunteered to do the job alone. He was warned that it was an impossible task for a Diploma work, but he was too enthusiastic to consider the friendly advice. It did not work out the way he had hoped; in fact, it did not work out at all. Luckily, he was able to fulfill his Diploma work requirement, but only barely.
He had to give up his hope of staying on at the university on a postgraduate fellowship. Instead, he was “distributed” to a radiology institute. Soviet graduates did not have the freedom to choose their jobs. The term “distributed” was the official Soviet technical term for assigning jobs to graduates. Zhabotinsky started his career in the radiology department of a medical institute specializing in cancer treatment. He spent most of his time in the library because in the department he found hardly anybody from whom he could learn anything.12
From time to time he returned for consultation with his former professor Simon Shnol in the biophysics department. Eventually, Zhabotinsky decided that he would formulate his own research project. Thus, the backwater character of his first workplace had one advantage in that it indirectly encouraged him to go his independent way. By this time, Shnol and his students had become interested in Belousov’s oscillating reaction, received Belousov’s recipe, and reproduced it in their experiments. Under Shnol’s influence, Zhabotinsky developed a research idea involving oscillatory phenomena in biochemical processes, such as photosynthesis. Shnol found Zhabotinsky’s goal interesting but not practical in that the necessary materials and instrumentation were not readily available to acquire for the grandiose project he had in mind. At this point Shnol raised the possibility that Zhabotinsky could pursue his postgraduate studies about Belousov’s reaction. Shnol had no doubt about the validity of Belousov’s observation; he had observed it with his own eyes, but he also realized that the real challenge was to understand the mechanism of the reaction.
A simplified description should help gain an understanding about oscillating reactions.13 For start, consider the reaction A + B → C + D in the presence of a catalyst X. Now, suppose that the mechanism could be reduced to two consecutive steps:
Here, during the reaction, the catalyst X transforms into Y, which is a different state of X, and X and Y display two distinctly different colors; the changes in their relative concentrations will appear as color changes. Initially, the reaction mixture displays the color of X. In reaction 1, in the presence of X, part of A transforms into C while X converts into Y. In reaction 2, in the presence of Y, part of B transforms into D, and Y coverts back into X. With the advancement of reaction 1, it stops at a certain point, because there is a finite amount of X, and when it disappears, the reaction cannot continue. Since Y is now present, the reaction mixture will display the color of Y; thus there is a color change. Reaction 2 now continues and as a consequence, X is being produced, which leads eventually to a color switch. But the presence of X makes the renewal of reaction 1 possible and the process continues as long as both A and B are present in sufficient amounts. The color changes appear as oscillations. They can be sustained if reactants A and B are being continuously fed into the system.
Oscillations can be illustrated with another example. Consider a system of rabbits (R), foxes (F), and grass (G), and consider the following events: The rabbits eat the grass and multiply (here let us assume that the grass grows continuously, so no matter how much the rabbits consume, no shortage of grass develops). The fast growth of the rabbit population, however, is adversely affected by the foxes because they eat the rabbits. As a consequence, the number of foxes grows—there are plenty of rabbits around so the foxes eat and multiply. As they eat the rabbits, the rabbit population diminishes, and at a certain point, the fox population stops growing, lacking sufficient food, and starts diminishing. The diminishing fox population favors the growth of the rabbit population, and so on.
To express this story like the reactions above, first, the growth of the rabbit population is described as R + G → 2R. Then, the growth of the fox population at the expense of the rabbit population is described as R + F → 2F. Before the total of R would become extinct, the F population starts diminishing for the lack of sufficient R, letting the R population grow again, and so on. The result will be a periodic change; starting with a certain rabbit population and fox population; a growth of the rabbit population, then a decline of the rabbit population, and the simultaneous growth of the fox population, followed by a decline of the fox population and growth of the rabbit population, and so on.14
Zhabotinsky did not hesitate to accept Shnol’s suggestion to make Belousov’s reaction his postgraduate project, but he did not want a conflict with the undergraduates who were already studying it. They were two female students; one was a fourth-year student, Anna Bukatina. Shnol was a popular student adviser; students were taken by his enthusiasm and the fact that he could suggest exciting and doable research projects even to undergraduates. Zhabotinsky thought that duplication of work on Belousov’s reaction would be superfluous, but if the students dropped the project, he would take it up. For the two students it was not difficult to drop this project because there were other intriguing problems that Shnol could suggest to them. Bukatina’s interest had already cooled anyway because she felt that the Belousov reaction had become “the subject of rather intense local interest and a high-profile topic, and she did not want to be involved with something like that.”15 She switched to a biological project, and her involvement with Belousov’s reaction did not fully stop, it was in a different aspect: she became Zhabotinsky’s wife. When their son, Mikhail, was born in 1964, his parents decided that he should have his mother’s Russian surname rather than his father’s Jewish surname. When the Bukatins moved to the United States, Mikhail became Michael.
As Zhabotinsky accepted Shnol’s suggestion, he started working on the reaction right away. At the same time, his previous idleness in his work place was changed into exciting activities, because in the meantime he had also changed his job. It was about a couple of months into his new job when Shnol gave him Belousov’s recipe on a piece of paper and he gave him also small amounts of the necessary reagents.
Zhabotinsky’s second position was again in a cancer research institute, but it was very different from the previous one. His boss was Leon Shabad, a world-renowned expert in cancer hygiene who maintained a strict order in the work place. This did not prevent him from developing good personal relations with all the members of his department, including the low-ranking ones, which was foreign to the Soviet medical community. Zhabotinsky’s task was organizing the analysis of cyclic hydrocarbons in car exhausts, and he was given independence to pursue this project. He purchased equipment, assembled the necessary instrumentation, and increased the sensitivity of the measurements by three orders of magnitude in comparison with the method that was used before. Once Zhabotinsky had organized the improved performance of his unit, he could return to his own research project.
Belousov’s recipe was simple and old-fashioned; Zhabotinsky had to weigh the reactants, dissolve them in moderately diluted sulfuric acid, and add water to reach the final volume. Once he had done all this, he could observe the oscillations in the color of the solution. The mixing and dissolving the ingredients produced a lot of heat, and this accelerated the reaction. The period of oscillations was rather short. Zhabotinsky devised a setup to record the oscillations, and repeated the experiment many times by using different amounts of reactants. Thus, he could see how the oscillations depended on the concentration of the solution. This was the easy part of the work.
Then came the more difficult part, understanding the mechanism of the reaction. Zhabotinsky and Shnol consulted Belousov (on the phone), and he had some ideas. Still, Zhabotinsky felt that he lacked experience and turned to Lev Blumenfeld for advice. Blumenfeld had acquired good training in quantum chemistry in the early 1950s, when quantum chemistry had become anathema for official Soviet science. Although this was a different area of research, Blumenfeld still gave Zhabotinsky useful pointers. He even wrote down a possible scheme for the reaction; it eventually turned out to be wrong, but it was a start. During this time, Zhabotinsky, in addition to his job, was a doctoral student of the university under Shnol’s supervision. Two years of uninterrupted research followed.
First, Zhabotinsky reproduced Belousov’s results. Then, he modified Belousov’s system and made it more convenient to study. Further, he succeeded in determining the mechanism of several steps in the oscillating reaction although he did not yet have a complete understanding of the mechanism of the entire process. Nonetheless, what he already had was deemed sufficient for his first paper. When Zhabotinsky was preparing his first manuscript for publication, he faced the problem of coauthorship. He wanted Shnol as coauthor, and he included Belousov’s name in the subtitle of the paper. He also wanted to show his draft to Belousov. Shnol declined coauthorship; for him, it sufficed to see the work progressing. He volunteered to send the draft to Belousov using the same means as he had received the recipe from Belousov. The manuscript came back from Belousov after two weeks with a nice note saying that Belousov was happy that someone was continuing his work, but declined to be a coauthor. In 1962, Zhabotinsky sent off the manuscript to the Soviet journal Biofizika (Biophysics).16 The article duly appeared two years later. The long wait for publication was quite normal at that time in Soviet scientific literature.
After having written and submitted his first paper, Zhabotinsky continued his research as Shnol’s doctoral student. His main contribution was in setting up the mathematical description of the various steps of the reactions. Mathematical modeling was his forte. His model helped him understand the mechanism of the missing steps of the oscillating reaction. Once he did, it became easy to devise new oscillating reactions that were similar to Belousov’s original reaction. What varied were the ingredients and the catalysts.
At this point, Zhabotinsky felt that he had completed his goal and embarked on preparing his second manuscript. He wanted it to appear fast. This could be possible if a full member of the Science Academy were to present his manuscript to the special periodical of the Academy called Doklady Akademii Nauk (Proceedings of the Academy of Sciences). He approached Aleksandr Frumkin, the renowned physical chemist and director of the Institute of Electrochemistry in Moscow (today, the Frumkin Institute), who himself had published two papers on electrochemical oscillations. It was the beginning of 1964, and it took two months for Zhabotinsky to make an appointment with Frumkin. The academician was known to read everything before he would sign anything. The wait was worthwhile, because once Frumkin gave his approval, it took only three more months for the paper to appear.17 However, this was a one-time opportunity only; Frumkin asked Zhabotinsky not to bring him any more manuscripts, pointing to a high stack of manuscripts on his desk, submitted by members of his own institute.
With his two papers and being the sole author for both—a highly unusual feat for a doctoral student, especially in experimental work—Zhabotinsky wrote his dissertation. It was on the topic of periodic chemical reactions in the liquid phase, and he defended it without any difficulty. Having thus earned his PhD-equivalent Candidate of Science degree, he was appointed as a junior research associate in the Institute of Biophysics. This institute had, in the meantime, moved from Moscow to Pushchino, a small town about sixty-five miles due south of Moscow. Zhabotinsky did not mind because he had a young family, and in Pushchino he had a much better chance of receiving an apartment than in Moscow; and this is what happened.
In Pushchino, Zhabotinsky’s perhaps most fruitful research period followed. An active group formed around him, and they had plenty of results. They generated considerable interest, first within the Soviet Union, but soon internationally as well. In 1966, they organized the first ever Symposium on Oscillatory Processes in Biological and Chemical Systems.18 At this symposium, Zhabotinsky was glorified, and the name Belousov-Zhabotinsky started being used. Belousov was still alive but did not attend; one can only hope that he felt satisfaction when he learned about the brewing triumph of his discovery. One of the most active participants in the meeting was D. A. Frank-Kamenetsky, the renowned nuclear physicist who had been one of the leading scientists at the secret nuclear laboratory Arzamas-16.19 Zhabotinsky was moving ahead with his academic career and in 1971, he defended his Doctor of Science dissertation.20 The culmination of his academic career during this period was the publication of his Russian-language monograph about the reactions with oscillating concentrations.21
Soon, Zhabotinsky’s interest turned to the application of oscillating reactions for modeling analogous biological processes. In some ways he was now reaching back to the original idea that his mentor, most realistically, did not find feasible for his doctoral studies. It is these biological relevancies that show the outstanding importance of oscillating reactions. For Zhabotinsky, the most attractive topic was the propagation of excitation in the heart. The normal operation of the heart is controlled by very long waves of excitation. He was familiar with the theory that attributed the most dangerous cardiac arrhythmia to the emergence of short spiral waves of excitation in the myocardium. But in talking with specialists, he found that very few of them believed in this theory. He and his associates—because he was now developing a strong group at the Biophysics Institute—started to study chemical waves in thin layers of solutions containing the oscillating reaction and found that they formed a wonderful target with spiral patterns, which were relevant to those in the myocardium. Their very first paper on chemical waves in two-dimensional media appeared in 1970 in Nature.22
Zhabotinsky experienced some difficulties in his personal life at this point that caused him to leave the Pushchino institute, and return to Moscow. Divorce and remarriage followed. Albina Krinskaya, the former wife of one of his closest colleagues, became his second wife. Zhabotinsky was looking for a place where he could continue his research, but it proved difficult. None of the research institutes of the Academy of Sciences in fields that would have suited his work had an opening for him. Finally, he was employed by the Institute of Biological Tests of Chemical Compounds, a new institution set up by the Ministry of Medical Industry. He was appointed head of the laboratory of mathematical modeling. The laboratory was staffed by only a small group, but it started growing as soon as Zhabotinsky joined it. Its coworkers were graduates of the biophysics departments of Moscow State University and the Moscow Institute of Physical Technology, both strong institutions. Soon, the group of about a dozen members was doing interesting work on the biochemical regulation in red blood cells.
At this time, Zhabotinsky’s interest shifted again, and he wanted to apply his knowledge to the improvement of cancer chemotherapy. He enjoyed having the independence to choose the research projects for his group, and he could make them appear attractive to his associates. They discovered a resonance response of dividing cells to periodic administration of highly intensive anticancer drugs. The essence of Zhabotinsky’s idea was based on the observation that chemotherapy has side effects, which can become lethal with increasing doses. The side effect manifests itself in the killing of healthy cells in addition to the cancerous ones. The solution may be to administer chemotherapy that would take into account the time scale of the cell division of healthy cells and thus avoid damaging them. Of course, there are many different kinds of the healthy cells, and this approach would first have to consider the most vulnerable cells. Once this was solved, the target for cell protection would be the next most vulnerable cells, and so on. This approach was promising for the development of more efficient chemotherapies for cancer because it would make it possible to increase doses without risking most of the healthy cells. They hoped that the same approach might be possible to apply in the struggle against AIDS as well. They had limited resources, but their expertise and dedication helped them a great deal in their efforts.23
This was a happy period for Zhabotinsky and this was also the only period in his life when outside recognition encouraged him in his activities. The idea of awarding a Lenin Prize to Zhabotinsky and three of his closest associates was born. It seemed increasingly realistic, and it was a big deal, because it was the highest scientific award in the country. A closer look, however, revealed a great deficiency in that Belousov’s name was missing from the initial list of awardees. The Lenin Prize can be bestowed posthumously, and it would have been utterly unfair not to include Belousov, even though he had been by then dead for years. It was through Simon Shnol’s organizational effort that, at the last moment, Belousov’s name was added to the roster of awardees. The winners received the Lenin Prize in 1980.
International fame, the Lenin Prize, and his exceptional creativity in target-oriented research did not, however, suffice to protect Zhabotinsky’s family from discrimination. Around 1980, upon graduation from high school, Michael Bukatin applied to the Faculty of Physics, Moscow State University, to be admitted as a student. This was the institution where his grandparents and his parents had studied, and Michael was a gifted and motivated student whose preparation included much from his family background that is not available in the school curriculum. Yet he was flunked in his physics entrance examination.24 Michael made another attempt two years later but to no avail.25 It was common knowledge that tacit instructions existed about limiting the number of Jewish students at institutions of higher education. This could not be given as reason for declining acceptance; so the university entrance committees administered the entrance examination in such a way as to make the applicant earn a failing grade. (I am sensitive to such injustice, having gone through a similar experience in my chemistry entrance examination due to “unfavorable” social origin, one generation before at Budapest University.26)
The 1980s were not a happy period in Zhabotinsky’s life. He experienced various bureaucratic difficulties in the management of the institute, which made his situation increasingly unbearable. Once again, he decided to leave. It took a while before he found another place. Only in 1989 was he able to join the National Scientific Center of Hematology, where he planned to apply the results on directing cell division to the treatment of leukemia. He had high hopes, but was disappointed when he was unable to get out of endless processes of reorganization. It was even worse when he was finally appointed to be in charge of a big and diverse department without any hope of doing reasonable research work any time soon. This happened when there was a rapid deterioration of science during the last years of existence of the Soviet Union.
Given this situation, it was a lucky development when in 1991 Irving Epstein offered Zhabotinsky a one-year visiting position at the chemistry department of Brandeis University. He joined the department and stayed there to the end of his life. Zhabotinsky was fifty-three years old; it might not have been too late to build up an independent career, but for him, apparently it was. His American period started well; he went for a lecture tour and visited a number of cities and universities. Back at Brandeis, he participated actively in discussions at seminars and in the research of his colleagues. Initially, he wanted his desk to be placed in a laboratory to be in the midst of the life of the group which he joined. Eventually he acquired his own office, but he still preferred spending his time in the lab.27
Lenin Prize winners, Albert Zaikin, Genrikh Ivanitskii, Anatol Zhabotinsky, Valentin Krinskii, immediately following the award ceremony at the Kremlin in Moscow.
Source: Courtesy of Michael Bukatin, Waltham, Massachusetts.
Anatol Zhabotinsky in 1995 at Brandeis University.
Source: Photograph by and courtesy of the author.
Memories of his experience during his years at Brandeis differ among his colleagues. The Hungarian visiting professor Miklós Orbán spent every summer for thirty years at Brandeis and overlapped with Zhabotinsky for seventeen summers. They had known each other since 1978. With Orbán, Zhabotinsky liked to talk about his father and about his own youth, but he avoided two topics: politics and science. Orbán’s impression was that Zhabotinsky did not feel at ease. On the other hand, he visibly enjoyed it when he could get involved in laboratory work, preparing solutions and participating in the experiments with his hands. Orbán and Zhabotinsky coauthored half a dozen publications. Zhabotinsky had a good number of joint papers with other associates of Epstein’s group, too, because he liked to involve himself in projects and make useful contributions. Alas, he hardly initiated new research. Orbán’s general impression was that somehow Zhabotinsky was left in the shadow during his American years.28
He was never appointed to a tenured position, and he held the title of adjunct professor for his last few years at Brandeis. This arrangement had its merits in that he did not have to teach much or to worry about proposals of his own; he could be engaged in what he did best—research. Yet he was in many respects less independent than he had been in his Soviet life, especially at the Institute of Biological Tests of Chemical Compounds. According to Shnol, the joyful and friendly atmosphere in which Zhabotinsky worked in Moscow and Pushchino contributed to his productivity. Shnol wondered whether Zhabotinsky’s lack of noteworthy results in his American period might be ascribed to his changed environment.29 However, even during his Soviet life, there were two sharply different periods. Through the mid-1970s, he was at his most productive; whereas after that, up to his departure, he was underper-forming compared with his prior achievements. In his American period, he had great productivity, except for the very last few years when an illness was gradually taking over. He never tried to capitalize on the authority of his name stemming from the fame of the Belousov-Zhabotinsky reactions.
The Belousov-Zhabotinsky reactions have much broader applications than what Zhabotinsky, let alone Belousov, might have envisioned when they started their respective work on them. To mention just one aspect of very general and fundamental significance, the reaction can be used to understand symmetry breaking—a literally vital characteristic of many life processes. Prigogine emphasized the importance of symmetry breaking in the most diverse processes. He stated:30
For me the most interesting thing is that far from equilibrium you automatically break symmetries. For example, in thermal diffusion, you create a situation where there are different concentrations in the “hot” part than in the “cold” part. Therefore, space symmetry is broken. Another example is the changing role of time. In the Belousov-Zhabotinsky reaction, for example, two instances of time are no longer playing the same role. At one point you have blue molecules, then yellow molecules, then blue molecules again, and so on. This is a time-symmetry breaking, but there are many other possibilities for symmetry breaking. The non-equilibrium structures have opened an entirely new chapter in symmetry breaking, and this may be not so familiar to some physicists.
The significance of Belousov-Zhabotinsky reactions is still being enhanced. Belousov did not live to see appreciation of his great discovery. However, Zhabotinsky saw real hope for continuation of their work. His full page obituary in Nature, alas, was—like Belousov’s Lenin Prize—a posthumous recognition. Zhabotinsky died in Boston, but his ashes are buried in Pushchino, near Moscow. His tombstone displays a scheme symbolizing the oscillating reactions, and the text carved into the stone reads: “founder of nonlinear chemical dynamics.”
