Rostislaw Kaischew and His Trace in the Fundamental Science. a Brief Historical Overview of the Genesis and Rise of Sofia School of Crystal Growth M

Bulgarian Chemical Communications, Volume 49 Special Issue C (pp. 23 – 41) 2017

Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview of the genesis and rise of Sofia School of crystal growth M. Michailov Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Science, Аcad. G. Bonchev Str., bl. 11, 1113 Sofia,Bulgaria

The process of nucleation and growth of crystals has great educational, historical and moral standing. is one of the most exotic phenomena in nature. This is because the birth and rise of the scientific Starting from disordered ensembles and small schools and their ideas mirror the noetic values of clusters of single atoms and molecules, matter mankind at the actual historical time [9-12]. organizes itself in beautiful figures and shapes with Prof. Iwan Stranski and prof. Rostislaw immaculate symmetry and ordering, ideal cubes, Kaischew, the founders of the most famous pyramids, needles, dendrites. These ensembles of Bulgarian scientific school have a dramatic crystal shapes and their divine beauty attend our personal and scientific destiny. Their illustrious entire being and consciousness, our entire life, they academic and research activity plays a key role in are everywhere around us. This incredible art of Bulgarian science as well as in the development of nature is generated spontaneously, without any the most important scientific institutions – the „St. influence of human mind, thinking, desire or action. Kliment Ohridski“ University of Sofia and the Why is this occurring and how? Where the science Bulgarian Academy of Sciences [2,4,5]. meets the unfathomable loveliness and marvelous aesthetics of the art of crystal growth? A substantial contribution in answering these fundamental questions of condensed matter physics is given by a very bright generation of Bulgarian scientists in the last century [1-8]. In the 1930s in Bulgaria originated the famous Sofia School of Crystal Growth, founded by the Bulgarian scholars prof. Iwan Nikolow (Nicola) Stranski and prof. Rostislaw Atanasov Kaischew. Brilliantly developed later, it is among the few internationally known substantial Bulgarian contributions in the world’s scientific history. How Iwan Nikolow (Nicola) Rostislaw Atanasov this school has been established? How an Stranski Kaischew internationally acknowledged scientific team, setting up the fundamentals of a novel theory in the Prof. Rostislaw Atanasov Kaischew was born on field of solid state physics, phase formation and February 29th 1908 г. In Sankt Petersburg in the crystal growth is affirmed in times of wars, family of captain Atanas Kaischew and Mrs. communist regimes and Berlin wall? How do the Anastassia Hadjimarinova. Both the genealogical names of its founders Iwan Stranski and Rostislaw lines of the Kaischew’s and the Hadjimarinov’s Kaischew manage to stand abreast with the names families are rather interesting. The roots of the of Josiah W. Gibbs, Walther Kossel, Yakov I. Kaischew’s ancestry have a history time line of Frenkel, Max Volmer and Frederick C. Frank? more than 250 years in the Rhodope’s village of Exploring these questions and primarily unriddling Chokmanovo, near Smolyan – a calm, peculiarly the genesis of the scientific schools by the picturesque site in the Rhodope mountain, beyond psychological and personal image of their founders the vanity and temptation of the modern world, urging the human mind to thoughtfulness, contemplation and existentialism, exciting curiosity and cognition [13,14]. To whom all correspondence should be sent: This small mountain village with almost 100 E-mail: [email protected] inhabitants (94 in 2011, but 941 in 1934), placed on  2017 Bulgarian Academy of Sciences, Union of Chemists in Bulgaria 23 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… sunny hills around green meadows and with several Kaischew takes part in the first and second Balkan small churches, has given birth to a remarkable wars and World War 1, later he is promoted as a number of scientists, writers, art directors, Chief of the Military Academy in Sofia, professor physicians, musicians, artists. The Chokmanovo in the General Staff Academy and one of the most village manifests specific intellectual singularity prominent Bulgarian military experts. The mother, with all the gifted persons born there. Only the Mrs. Anastassia Hadjimarinova also originates people with academic rank and degree, originated from a famed Bulgarian family of large landowners from this very small village, are more than 20 [14]. and merchants from the region of Stara Zagora. In The Kaischew’s family also belongs to this unique 1913 the family moves to Sofia. Their son ensemble of remarcable personalities. Rostislaw graduates from high school in Sofia and matriculates at the Department of Physics and Mathematics of Sofia University. In his third years he attends the lectures in physical chemistry of Iwan Stranski, recently appointed as a professor at the University.

Iwan Stranski Rostislaw Kaischew, 1939 At that time, Stranski involves Kaischew in scientific activity and between them grows a tight collaboration and, later, an amity. Their first joint paper, entitled “On the equilibrium shapes of homopolar crystals”, initiated already in the time of the student years of Kaischew, is published in 1931 Chokmanovo village and the Kaischew’s family house, [15]. After his graduation from Sofia University, 2014 г. Kaischew accepts a Humboldt scholarship, recomended by Stranski, and in 1930 leaves for Berlin to the famous scholar and keen connoisseur of thermodynamics, Francis Simon. Simon is a person with exeptional individuality and flavor, disciple of Walther Nernst, the founder of the Third Law of Thermodynamics. In 1931 Simon becomes a professor of physical chemistry at the Laboratory of Low Temperatures at the University of Breslau (presently, Wroclaw, Poland). Two years later, in 1933, he moves to the Portrays of general Atanas Kaischew and prof. Rostislaw famous Clarendon Laboratory at the University of Kaischew in the municipality of Chokmanovo village. Oxford, invited personally by Frederic Lindemann. In 1905, the father of prof. Kaischew, Captain Later, in 1956, he becomes head of the Laboratory. Atanas Kaischew is recruited to Sankt Petersburg, Simon performs extraordinary, pioneering research where he graduates with excellence „summa cum in the field of low temperature physics. He laude“ from the General Staff Military Academy. A succeeds to liquefy helium for the first time in the few months after Rostislaw was born in 1908, the world by means of a system of magnetic cooling, family returns to Bulgaria. General Atanas based on adiabatic demagnetizing. Together with his assistant, Nicolas Kurti, he attains 24 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… experimentally a temperature of 1K (one micro separation of uranium isotopes via gaseous kelvin), which is considered as a feat of the diffusion and production of uranium-235. He is one experimental physics at the time. Simon of the principal scientists, taking part in the investigates and introduces the basic method for physical design and creation of the nuclear bomb with the so-called „Manhattan Project“ [16].

Sir Francis Simon (the man with the hat at the second row) at the annual meeting of the Bunsen Gesellschaft, may 1928 in Munich, accompanied by Walther Kossel, Kazimierz Fajans, Peter Debye, Fritz London. (G.F.Hund, https://commons.wikimedia.org). As a disciple of Francis Simon, Kaischew lands Reining in that group are excellent scientific in the surroundings of notable researchers and gains ambiance and sincere, artistic relations. There, a great opportunity for academic development and Kaischew starts for the first time in the world the scientific life. In Berlin he attends lectures by study of the basic thermodynamic properties of Nernst, London, Simon and Bodenstein. In March liquid and solid helium. In these pioneering studies, 1931 Francis Simon is invited to head the Institute he determines experimentally the density and the of Physical Chemistry at the University of Breslau heat of fusion of solid helium in equilibrium with and his entire research group, including the the liquid phase, its specific thermal capacity, assistants Nicolas Kurti and Kurt Mendelson as compressibility and other fundamental physical well as the doctoral students Heinz London (brother quantities. These experiments open up a way to of the famous Fritz London who introduced estimate the so-called „zero entropy“ in the Nernst’ London‘s forces) and Rostislaw Kaischew, moves theorem – a subject of a large discussion at that there. time. Kaischew‘s results will be used later in the interpretation of the Nernst-Simon formulation of the Third Law of Thermodynamics, in the form that a thermodynamic process, bringing a system to the absolute zero temperature by means of a finite number of steps, is impossible [16]. Kaischew defends his doctoral thesis on November 7th, 1932 with excellence „summa cum laude” and becomes the first doctor of the Institute of Physical Chemistry at the University of Breslau. The results of his dissertation are published in the famous journal “Nature” in 1934 in collaboration with Francis Simon - „Some thermal properties of condensed helium“. Let us point out that it has been possible to publish even preliminary results in “Nature” in these years [17]. During his stay in Breslau, Kaischew maintains active correspondence with Stranski, who is in Berlin at that time. In this way is completed their Rostislaw Kaischew at the University of Breslau, 1931. first theoretical study. The paper ”On the 25 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… equilibrium shapes of homopolar crystals”, shape. This definition of equilibrium formulated in published in “Zeitschrift für Physikalische Chemie” a completely new way, different from that of the in 1931, marks the beginning of the theory of mean classical thermodynamics of Gibbs, i.e. by the separation works [6, 15]. It is shown for the first binding energy of a separate single element of the time in this paper, that only atoms or molecules crystal lattice (atom or molecule) will lay the bound stronger than in the site of half-crystal cornerstone of the entire construction of the new position (kink), can belong to an equilibrium crystal molecular theory of crystal growth.

The doctoral thesis of Kaischew, Breslau, 1932 (left), Kaischew at the Low Temperatures Laboratory, Breslau, 1931, (middle), the publication of Kaischew and Simon in Nature, 1934 (right). The time spent in Breslau, in Simon‘s group, assistant, without any emolument. Only six months shapes the basic path of scientific evolution of later, the efforts of Stranski with the Ministry of Kaischew’s life characterised by deep involvement Education succeed and Kaischew is inaugurated as in the world of scientific thought. Being a part of a a full-time assistant at the Department. At that time, research team in which many of its members Heinz the oldest scientific colloquium in Bulgaria is London, Nicolas Kurti and Kurt Mendelson will instituted, still existing today as the „Stranski- become Fellows of the British Royal Society, and Kaischew Colloquium on phase formation and Nicolas Kurti its vice-president (1965-1967), crystal growth”. This informal forum of Kaischew gains a remarkable start for scientific discussions, with its first members Iwan Stranski, activity and career. Furthermore, he shapes his Rostislaw Kaischew, Stefan Christov, Lubomir personality in environment of extremely variegated Krastanov, Dimitar Totomanow, will play later a and often exotic cultural interests. Besides his key role in the creation of entire generation of achievements in the field of low temperature researchers. The topics of the discussions are not exprimental physics, Nicolas Kurti becomes one of restricted to phase formation and crystal growth, the founders of the so-called “molecular cuisine”, but cover a broad range of contemporary, cutting- moderates a number of cooking shows on BBC and edge problems of condensed matter physics and organizes the first colloquium on “Molecular and physical chemistry. Physical Gastronomy”, held in Erice, Italy in 1992 The time between 1933 and 1936 is the most [18]. Kurt Mendelson becomes famous with his valuable period of the research collaboration treatise on the origination and construction of the between Kaischew and Stranski. This remarkable Egypt Pyramids, too [19]. scientific communion and empathy result in a Already affiliated intellectually to the cultural ceaseless friendship. Thus, in a sequence of five and scientific values of the Western world, papers in 1934, are presented the basic ideas and Kaischew returns to Bulgaria and enters the models of the theory of mean separation work [6, Department of Physical Chemistry of Sofia 20-24]. The new theoretical model of Stranski and University, headed by prof. Iwan Stranski. Kaischew considers for the first time the Kaischew starts his career as a volunteering equilibrium and the growth of the new phase at the 26 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… molecular level, from the viewpoint of the kinetics In 1935 Kaischew leaves for three months to of elementary steps in phase formation and crystal Kharkiv, to the Physical and Technical Institute of growth. Furthermore, it complements in a perfect Ukraine, recommended by Martin Rueman, senior way the classical Gibbs thermodynamic model of assistant of Simon. There Kaischew works on the phase formation, demonstrates the identity of the adiabatic effect of nitrogen expansion at liquid two models and thus attains a great physical helium temperatures. During his stay in Kharkiv, he importance. 60 years later these envisaged model gives a lecture on the method of mean separation concepts will be visualized at the atomic level by work, presenting the results obtained under the the brilliant Scanning Tunneling Microscopy guidance of Iwan Stranski. There he meets for the experiments of Joost Frenken, presented at the first first time the famous theoretical physicists Lev D. “East-West Surface Science Workshop”, Landau and Evgeni M. Lifshitz, who take part in EWSSW‘94 in Bulgaria. the discussion of his lecture.

The original record and part of the lectures presented at the Colloquium of Physical Chemistry in 1932/1933 at the Department of Physics and Mathematics of Sofia University. After five years career as a full-time assistant at Sofia at the end of September 1938 comes the end Sofia University, Kaischew attains the possibility of his romantic student’s life. From now on, he for a sabbatical year abroad. So, he leaves for starts his own, individual way, the most important Germany in 1937 with a Humboldt scholarship to and most interesting part of his life leading to the prof. Klaus Clusius at the Institute of Physical creation of the Sofia School of crystal growth. Chemistry of Munich University. Clusius is a Looking into Kaischew‘s life in science, it is student of Arnold Eucken of Göttingen, and later is important to consider the more general question, the leading scientist and the head of the German that of the birth and rise of scientific schools. Is it experiments on the production of heavy water. an individual feat and goal of a single highly Together with his assistant Gerhard Dickel he erudite person, just a prodigy, or a natural, develops the method of separating isotopes by synergetic process of self-organization of highly means of thermal diffusion. In the Clusius group, capable and motivated team of researchers Kaischew retains his interest in the field of low following the same scientific ideas in the presence temperature physics and investigates the of a distinguished leader with strong personality crystallization of carbon monoxide by slow and character? How does the generation, condensation from the gaseous phase and the development and recognition of a scientific society conversions of condensed hydrogen halides by which designates the tracks of scientific vogue in a means of polarization microscopy. These studies given field depend on the enviroment in which it are published in the “Zeitschrift für Physikalische exists? A retrospective survey on the Sofia School Chemie” in 1938 and 1939. This sabbatical year in of crystal growth would throw a light on these Munich spent in the bachelor company of two other heuristic questions. scholarship fellows and his friends Sazdo Ivanov Science is a luxury exercise of the human soul, and Georgi Bradistilov is one of the happiest set up with time, assiduity, curiosity and moral. It is periods in the life of Kaischew. With his return to a state of constant dreaming. Allegiance to science 27 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… and the affiliation to the academic world is, in knowledge and intuition of separate investigators, itself, a great human privilege, based on the desire the specific scientific school has the opportunity to and ability to study oneself in relation to the create a more general (to some extend) picture and structure, logic and aesthetics of the world outside. scenario of the phenomena in a given field, to It is a far, long-distance mental horizon depict the outlines of the future scientific reserarch overreaching the everyday existence and the and finally to rationalize the scientific curiosity. personal life. However, the individual ability of Let us point out that the outstanding feature of contemplation and reasoning is not sufficient for such ensemble of sinergy-associated shcolars the construction of cognitive image of the nature. cannot be obtained by simple gathering or just The retrospection shows that fundamental human assembling of well-known theoretical and knowledge is often formed not by individual experimental models, all created by individual achievements and discoveries, but by scientific skilled researchers. The only real recognition of any schools that provide direction, style and meaning of scientific school is its influence on the international the scientific research. The formation and scientific community and the worldwide credit for development of these schools determines the its achievements. Furthermore, the great scientific understanding of fundamental laws of the ambient schools are distinguished not only by their world for prolonged periods of time. This process contribution to specific field of knowledge, but also of self-organization of knowledge is an archetype by their impact on the entire human knowledge and of the human soul, occurring as a result of the human values [9-12]. capability of thought to arrange and construct In line with the above psyhological path of the various logical and physical models and to project genesis of scientific schools, the birth and evolution their evolution in different temporary and spatial of the Sofia School of crystal growth could be directions. Therefrom stems the essence of the classified scientifically, thematically and scientific schools, namely heuristic classification of historically in three time periods, each of them knowledge in a particular scientific field, creation having its specific scientific achievements and own of highly competent scientific environment, setting research glory and drama. It is important to stress, the direction and dynamics of the discussions in the however, that Kaischew’s great supervisory power field, and formulation of the scientific paradigms at and style are natively governing the scientific a particular historical moment. In this way the ambience in all these periods. In some cases his scientific schools outline and decorate the ranges of attendance is a strong motivation for the human knowledge in historical context [9-12]. researchers, in others it is a wall against mediocrity, A basic feature of every scientific school is its speculation and conjecture, and in others it is just a ability to attract and educate young researchers. It great emotional reminiscence of the old times of should be emphasized that the scientific schools do nascence of the School. not represent simply an aggregation or a team of The first period (1927 – 1944), marked by the gifted researchers. Teams of scientists exist in initial development of the molecular theory of many research laboratories around the world. The crystal growth, has a remarkable pre-history. The presence of various scientific ideas, theoretical time when Kossel and Stranski introduced the models, experimental observations and experienced concept of ‘kink’ or ‘half-crystal position’ that researchers is by far not a sufficient condition for would play a fundamental role in the study of the genesis of a scientific school. Going back in the nucleation and growth of crystals, is a time of history of human knowledge, we observe that the impetuous rise of new ideas and discoveries in the formation of scientific school is a rather complex physical sciences. phenomenon, grounded on an ensemble of In 1927 the Belgian Jesuit cleric Georges scientific paradigms, competence, imagination, Lemaître creates the Big Bang theory for the birth academic freedom and particular taste for research. of the Universe. The principles of the quantum These characteristics, however, are still not enough. theory are formulated in 1925 - 1927 and accepted The presence of a glamorous, authoritative and by the international physical community, after influential personality is compulsory to attract dramatic discussion, at the 5th Solvay Conference in researchers, to focus scientific curiosity and most of 1927. The electron microscope is invented by Ernst all to guarantee academic freedom and unrestricted Ruska in 1933, Paul Dirac predicts the existence of discussions for all researchers. This excites a strong antimatter in 1928. Entirely new model concepts synergetic behavior along with cognitive and about the crystal structure are developed by the mental processes leading to a very distinctive solid state physics. In 1918 Erwin Madelung heuristic state of the scientific school. In that state, studies the interactions in the crystal lattice of as a result of interaction and integration between sodium chloride and defines the “Madelung 28 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… constant”, relating the electrostatic potential of outcomes of the theory of Stranski and Kaischew is interaction to the parameters of the crystal lattice. that it reveals and proves the identity of the Max Born and Otto Stern introduce in 1919 the classical Gibbs thermodynamic approach with the definition of surface energy by means of the energy kinetic treatment of phase formation. On that of creation of new surface at splitting the crystal background, the most fundamental and intriguing along a certain, well-defined crystallographic plane. problems in nucleation, equilibrium shape and growth of crystals, thin film formation and epitaxy may be studied in great detail. Stranski and Kaischew publish their great theoretical papers in the field of phase formation and crystal growth during the period 1931 – 1936. As already mentioned, in their first joint paper, published 1931 in Zeitschrift für Kristallographie, „On the equilibrium shape of homopolar crystals“, they show that only atoms, bound more strongly than those in the kink position, can belong to the equilibrium shape [15]. On the basis of these Walther Kossel Iwan Stranski calculations, the method of mean separation works is introduced, which reveals a remarkable The Wulff theorem for the polar diagram of the agreement of the theoretical with the specific surface energy of a crystal is introduced in experimentally observed shapes of various metal 1901 (it has been proved much later by Herring, crystals, grown via condensation from the gas 1956) [7,8,25,26]. All these impressive scientific phase. The introduced mean separation work, a discoveries prepare the creation and development quantity determined from the disassembling of the of a new molecular-kinetic theory of crystal growth outermost rows of growth units at the periphery of a as one fundamental theoretical model in the solid two-dimensional crystal, provides the possibility to state physics. The introduction of this theory is not formulate, by means of kinetic reasoning, the an accidental phenomenon. It follows however the Gibbs-Thomson equation for the equilibrium of heuristic logic and appears as a part of the whole small, finite-size crystals, as well as the Gibbs- remarkable ensemble of scientific achievements Wulff theorem for the equilibrium shape of generated during the thirties and forties. crystals. With the mean separation works, it Such is the dynamics of the physical research in becomes possible to determine the supersaturation the world, when the Department of Physics and dependence of the energy barriers for attachment or Mathematics of Sofia University becomes one of detachment of growth units (atoms or molecules) at the international scientific centers, where the various positions on the crystal surface. In this way, molecular-kinetic theory of crystal growth emerges the probabilities of nucleation and dissolution of and develops (1927 – 1941). At that time Kossel arbitrarily sized two-dimensional and three- and Stranski introduce the separation work of the dimensional nuclei on a crystal surface can be crystal building units as a measure of the crystal calculated. Thus, the crystal nucleation and growth lattice energy and determine the separation work rates are determined for the first time from kinetic for an individual structural element in the special, point of view. Kaischew publishes the first papers “kink” position on the crystal surface. These on the kinetic treatment of the nucleation of crystals quantities are crucial for understanding the and gaseous bubbles together with Stranski in 1934 proposed new model of crystal growth at the [6]. molecular level. They form the basis of the theory One of the most famous and striking of mean separation works, developed later in the achievements of the Sofia School of crystal growth thirties, which demonstrates the first kinetic during this period is the unveiling of one of the treatment of the equilibrium and growth of crystals. basic mechanisms of nucleation and growth of thin A remarkable advantage of this theory is that it epitaxial films. The mechanism of layer-by-layer gives for the first time a clear notion of the basic growth of ionic crystals of NaCl is unravelled in phenomena in crystal growth at the molecular level detail in an original paper of 1939, summarizing the by considering a maximally simplified model PhD thesis of Lubomir Krastanov, done under the crystal, namely the Kossel crystal. Furthermore, the supervision of Iwan Stranski. Although the new theory opens the way to estimate the phenomena of epitaxial growth are not directly interaction energies between the particles setting up discussed in a proper way in the paper, the crystal lattice. One of the most beautiful the mechanism of nucleation and growth of lattice 29 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… planes of heteropolar ionic crystals, proposed growth mode (Frank-Van der Merve) to three- therein, represents a realistic physical model of dimensional (Volmer-Weber) mechanism of heteroepitaxial growth. This gives a reason heteroepitaxial films formation. Thus, depending on to Ernst Bauer in 1958, in his classification of the the ratio of cohesion and adsorption energies of the basic growth modes of thin epitaxial films atoms of the crystalline phase and on the misfit grounded on the subtle competition between between the lattices of substrate and film, one the surface energy of the substrate, the film, and or several two-dimensional, entirely completed the interface between them, to name the monolayers are formed at the epitaxial interface, Stranski-Krastanov growth mechanism this followed by the nucleation of three-dimensional extremely frequently occurring mechanism of clusters. This very frequently encountered mecha- heteroepitaxial film formation [27-29]. nism of growth of thin epitaxial films follows This mechanism explains the initial stages of directly from the remarkable paper of Stranski and transition from two-dimensional, layer-by-layer Krastanov in 1939.

The “great trinity” – Rostislaw Kaischew (left), Iwan Stranski (middle) and Lubomir Krastanov, the dissertation of Krastanov (middle), and the original Stranski-Krastanov paper of 1939 (right). The achievements of Stranski, Kaischew and admirable way when the Department of Physical Krastanov, the “great trinity” (see the picture) in the Chemistry is constituted at the Institute of Physics field of phase formation, presented so far, mark the of the Bulgarian Academy of Sciences (BAS) in beginning of the Sofia School of crystal growth. 1947. As head and founder of the Department, he Kaischew is appointed as a private docent appoints his first collaborators: Jordan Malinovski, (associate professor) at Sofia University in 1941, Boyan Mutaftchiev and Dimitar Nenov, as well as regular docent in 1944, and professor in 1947. the laboratory assistant Valentin Hitov. Later, During that time, as well as for a long time after, he Alexey Scheludko, Georgi Bliznakov and Evgeni is involved in extensive teaching and university Budevski join them. These Kaischew’s disciples activity. In the period 1944 - 1962 he is head of the become the core of the established later, in 1958, Department of Physical Chemistry at Sofia Institute of Physical Chemistry of BAS. In the University. His lectures on physical chemistry, following years some of them, doing pioneering delivered many years keep on being a basic source research, succeed to launch brand new directions in for the education of young researchers and doctoral the physical chemistry of surface phenomena (A. students in this field. It can be stated that at the end Scheludko), photographic processes (J. of the 1930s, having published the main papers on Malinovski), electrochemical kinetics (E. the model of mean separation work, Kaischew is a Budevski), quantum theory of electrode processes well-established scientist already. From this time on (S. Christov). These new research lines comprise begins the second period in the rise of the Sofia the image of the Bulgarian physical chemistry School of crystal growth, covering the time from during the twentieth century. As mentioned, the 1944 to 1990. Department of Physical Chemistry of the Institute The endowment of Kaischew to organize of Physics has been transformed in the autonomous scientific investigations, to formulate problems, to Institute of Physical Chemistry in 1958, and prof. introduce significant topics, to assess and involve Rostislaw Kaischew is appointed as its first gifted people in research teams around himself and Director. Herewith begins the best organized, most of all to make science according to West scientifically and thematically structured period in European standards develops and expands in 30 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… the development of the already existing Sofia large-scale scientific style would be impossible School of crystal growth. without another feature, which is ever less The foundation of the Institute of Physical frequently encountered in our time. This is his Chemistry follows the line of natural expansion of uncompromising honest attitude towards the results successful scientific investigations. The aim was to of any research. His erudition does not allow concentrate and motivate tightly the research in the scientific dodging. But maybe most impressive is fields of thermodynamics and kinetics of phase his aptitude to acknowledge his own fault, when formation and crystal growth on the ground of something turned to be different from his ideas. already well-established scientific teams and their Kaischew never published incomplete results or proven achievements. Five departments are formed results without clear physical interpretation. under the leadership of prof. Kaischew: Department Furthermore, Kaischew requires himself to be of Phase Formation and Crystal Growth, deeply and tightly convinced in the physical Department of Surface Phenomena and Dispersion rationality of the models providing the results. A Systems, Department of Physical Chemistry of good example of this attitude is the so-called Photographic Processes, Department of “rebellion of the young”. At the end of the 1950s Electrochemistry, and Department of Kinetics and part of the young collaborators - Malinovski, Catalysis. The initial subject line of the Institute Scheludko, Budevski, Bliznakov - express their follows the development of the existing theory of discontent, because they have worked hard and phase formation and the model experiments accumulated a huge amount of experimental results, planned to prove the fundamental concepts in the which however are not published, because not field of crystal growth. Leading role at this stage of everything has been explained and interpreted. the history of the Institute plays the remarkable and Kaischew reacts emphatically: “Out of question, versatile scientific erudition of Kaischew, allowing you may publish! I do not object. But without me!” infallible and intuitive treatment of the core of [4]. It is difficult to find a better proof of scientific scientific problems. His direction follows the sense style and honourability. This is the ambiance, in and the clear formulation of the problems, the which begin the most important years in the collaborators are always included in the process of development of the Sofia school of crystal growth. discussion and decision making – a feature, which The scientific style of Kaischew, built up in is often lacking in the scientific management of Europe and directed towards fundamental scientific researcher teams. problems, is in clear conflict with the formal Kaischew’s scientific and administrative scientific policy of the communist regime in management transform the Institute of Physical Bulgaria in the 1960s, known as “science for the Chemistry into a leading scientific structure in people”. Kaischew succeeds to find a compromise Bulgaria, where the development of the school of and to preserve the fundamental studies at the crystal growth founded by Stranski and himself is Institute. In a very clever way, he constitutes a maintained. How should an internationally special department for applied research, thus respected scientific institution be constructed to formally consenting with the required public image become an academic standard in the Bulgarian of “studies for the practice and for the national science? As already mentioned, two basic economy”. In this way his collaborators doing prerequisites are necessary for that – availability of fundamental research are not compelled to deal a competent and leading personality and capable with, often preposterous, applied and industrial assistants. Kaischew owns both. His talent and problems. However, the most important willingness to fascinate young people for research achievement and great benefit of this fine and is remarkable. Kaischew lures his collaborators not complicated process of juggling are the very good with rapid career or monetary promises, but with relations between the collaborators dealing with the sense of what they are doing. The strength of fundamental and applied research. He persuaded all this talent is revealed not only by his purely scientists in the institute that the applied studies can personal qualities, but most of all by his ability to be successfully performed only in close relation and point out and demonstrate the horizon of any interaction with the fundamental investigations. scientific research. The particular problems are This was also proven by a number of excellent turned to merely steps towards the main task of the works done by the Department of Electrochemistry scientific study. This feature of Kaischew‘s that solved in spectacular way many scientific style is a strong motivation for his technologically essential problems. Possessing a collaborators. Kaischew does not allow for good understanding about the significance and the mediocrity and sets extremely high scientific long distance horizon of fundamental science, criteria at the Institute of Physical Chemistry. This Kaischew succeeded to keep it at the Institute and 31 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… to ensure calm and comfortable environment for experiments of the Sofia School are presented today research. In this environment, his most gifted in every textbook on crystal growth. disciples Evgeni Budevski, Jordan Malinovski, In the middle of the 1960s, Jordan Malinovski Boyan Mutaftchiev, Ivan Gutzow, Svetoslav and Ivan Konstantinov started new exciting Toschev, Dimitar Nenov and later on Dimo investigations of the mechanism of the Kashchiev, Ivan Markov, Stoyan Stoyanov, photographic processes in silver bromide single Alexander Milchev, Christo Nanev form their own crystals. They made a notable contribution in the research style and notable scientific achievements. study of the “latent image” in the photographic In this way, a remarkable reputation for the Institute processes, i.e. the invisible image, formed by is built up in the country and internationally, too. irradiation of photosensitive materials, which is One of the most distinguished students and a visualized later by means of chemical or physical coworker of Kaischew, Boyan Mutaftchiev after development. The unique results demonstrate the emigration in France conducts in the 1980-90s a essential role of the so-called photo-holes the number of Laboratories and research teams in the generated by light irradiation modification of silver field of phase formation and crystal growth at the halides. The formulated new theory is French National Center for Scientific Research, acknowledged in the photographic science as the CNRS, (Centre National de la Recherche “Malinovski symmetric scheme”, which accounts Scientifique) in Marseille, Nancy and Paris. The for the contribution of both electrons and photo- raising of collaborators with their own scientific holes. face and profile is a particularly important quality This impressive development of the studies in of Kaischew style, which proves to be very the field of phase formation and crystal growth at significant for the creation of scientific school. the Institute of Physical Chemistry gives birth in In this atmosphere at the end of the 1950s and 1967 of two new, separate Laboratories – the the beginning of the 1960s starts up the Central Laboratory of Electrochemical Power development of unique experimental methods for Sources and the Central Laboratory of studying morphological changes of crystal surfaces Photographic Processes. Founders and leaders of and determining their growth rate, the double-pulse these laboratories are the most brilliant disciples of method for kinetic investigations of electrochemical Kaischew – Evgeni Budevski and Jordan nucleation, the capillary technique for Malinovski. These two internationally recognised electrochemical growth of single crystals. All these scientists initiate entirely new directions in the novel methods play a key role in the later long-time fields of electrocrystallization and photographic experimental investigations of various aspects of processes. It has to be noted however, that the new the nucleation and crystal growth phenomena. New scientific organizations appear undoubtedly as a studies are initiated revealing the impact of result of Kaischew’ scientific role and style, adsorption of foreign particles during the growth of academic spirit and uncompromising, tight crystals and the role of the active centers for scientific criteria. These laboratories, graduated condensation in the formation of crystal nuclei. from the Kaischew School with “summa cum One of the most remarkable achievements of the laude”, turn to be the prodigy of the Institute of Kaischew School in the 1960s are, however, the Physical Chemistry. Another of the most promising brilliant experiments on electrocrystallization, colaborators, Georgi Bliznakov, heads the Institute revealing the mechanisms of crystal growth by two- of General and Inorganic Chemistry in 1960, and dimensional nucleation and spiral growth. The the Department of Kinetics and Catalysis moves capillary method of growth of silver single crystals there. Later, in 1983, this Department is with separate dislocation-free crystal faces, created transformed into a separate Institute at the by Kaischew, Budevski and their collaborators, as Academy of Sciences. With the creation of these well as the obtaining of crystal faces intersected by individual scientific institutions begins the time of a single screw dislocation allow to demonstrate, expansion of the Sofia School of crystal growth. study and prove in a spectacular way the two basic In the 1960-70s the closest collaborators of mechanisms of crystal growth, namely, the layer- Kaischew succeeded to attract young physicists and by-layer growth by two-dimensional nucleation and chemists, talented and well-motivated, just the screw dislocation growth [6,30-33]. These graduated students, to the Department of Phase experiments settle one of the most famous scientific Formation and Crystal Growth. They join the discussions open by Sir Charles Frank during the Kaischew team with a great ardor and eagerness to Bristol conference of the British Royal Society in grow up in knowledge. The Kaischew team of this 1949 about the role and significance of these two Department is called by their colleagues from other fundamental mechanisms of crystal growth. These academic institutions “the Kaischew gang”. They 32 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… have the attitude that they belong to a different from active scientific work and administration as a scientific environment, maintaining high scientific Head of the Institute in 1989. criteria, free communication, good-humored Still, the large-scale way of thinking inherited curiosity and profound knowledge. A particular role from Kaischew, leads and motivates his plays the still active Colloquium on Phase collaborators in the establishment of new Formation and Crystal Growth founded by Stranski, interdisciplinary topics that expand the scientific as mentioned, as far back as in the 1930s. This activity of the Institute of Physical Chemistry. Colloquium keeps on being the academic location Several research teams are formed dealing with the for specialized discussions of a broad range of ideas crystallization of proteins, electrochemical not merely from the field of crystal growth, but also formation of conductive polymer films and metal- from materials science, soft matter physics, polymer nanocomposites, atomistic simulations of biophysics and computer modelling. diffusion phenomena at epitaxial interfaces, Enirely new leading lines of investigations are modelling the structure and thermodynamic formed in the following years at the Institute of properties of nano-sized atomic clusters, quantum Physical Chemistry. Studies on formation and nanowires and polymer systems. Applying basic development of morphological instability of the thermodynamic and kinetic models of the classical growing crystals, the atomistic theory of nucleation theory to new objects, such as protein crystals or in electrocrystallization, theoretical and thin conductive polymer films, quantum atomic experimental studies of non-stationary effects in nanowires, biopolymers and biological systems, nucleation, the mechanisms of epitaxial growth, results in revealing new important regularities in atomic structure and properties of epitaxial Nature. interfaces, surface diffusion phenomena turn to be The scientific ideas and results of the scientists dominant accents. An expression for the non- belonging to the Sofia school of crystal growth are stationary nucleation rate is derived, which is presented in thousands of publications in renowned widely used in the understanding of the results on international journals, book chapters, monographs crystallization kinetics. A general theorem of and review papers. Since the formation of the nucleation is proven, connecting the nucleation Institute of Physical Chemistry in 1958, its work, supersaturation and nucleus size. Being members have published over 3 400 scientific generally accepted in the literature and it is used in papers in specialized and referred scientific studying the formation of bubbles, droplets and editions, cited over 35 000 times by other authors. crystals, since it does not involve any theory to Distinguished disciples of prof. Kaischew, icluding determine the nucleus size. Studies are initiated in Evgeni Budevski, Boyan Mutaftchiev, Ivan the field of glassy state, crystallization of glass and Gutzow, Ivan Markov, Dimo Kashchiev, Alexander new materials of glassy ceramics. Milchev, Georgi Staikov, issued in most renowned Investigations of the processes of phase scientific publishers their monographs as formation by means of computer modelling start at originating from the Department of Phase the Institute of Physical Chemistry in the 1980- Formation and Crystal growth at the Institute of 90s. For the first time it is possible to solve exactly Physical Chemistry [34-40]. Collaborators and a number of “insolvable” problems that could not disciples of Kaischew in the Department of Crystal be approached theoretically due to the unavoidable Growth, including Andrey Milchev, Stoyan approximations needed for the formulation of Stoyanov, Christo Nanev, Isak Avramov, Vessela the theory. With this novel and powerful method, Tsakova, Michail Michailov, have been invited to complex phenomena in thermodynamics and write book chapters and reviews, devoted to kinetics of crystal growth are studied, such as two- modern fields in surface physics, crystal growth, dimensional phase transitions, atomic surface electrocrystallization, computer modelling of roughness, growth of epitaxial films, interfaces, crystallization of proteins, etc., based on two-dimensional surface alloyng at epitaxial the investigations in the Institute of Physical interfaces, thermodynamic properties of atomic Chemistry [41-52]. The inherited scientific style clusters, nanocrystals, structure and properties motivates the members of the Kaischew School to of quantum nanowires and nanocomposite keep this publication activity, despite of the grave materials, diffusion transport phenomena, structure financial pressure and the public contempt felt by of interfaces, macromolecular and biological the scientific community in Bulgaria during the last systems. twenty years. The third period in the development of the Sofia The story of creation and raising the Institute of School of crystal growth starts in the 1990s, Physical Chemistry and particularly the Department coinciding with the withdrawal of prof. Kaischew of Phase Formation and Crystal Growth has one 33 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… extra dimension besides the purely scientific demonstrated that for him happiness and gladness features. It is due to the remarkable charm and are a question of character, but the sense lies strong personality of Rostislaw Kaischew. Without in the seeking. There were, of course, such people taking into account this dimension, the narrative of who could not accept his academic enchantment, the general development of the Sofia School of intelectual power and scientific erudition. Most of crystal growth and the Institute of Physical all, those were people far below his class, who were Chemistry would have an ordinary, commonplace simply envious. and maybe even trite, character. Following this The discussions in the Colloquium of Phase phychological line, it is worth noting one of the Formation and Crystal Growth presented most striking features of prof. Kaischew’s an emanation of Kaischew’s criteria and style in character. This is his fine ability to mix the science. His comments on the reports and lectures academic discussions with human sentimentality. always touched the physical core of the problem On the face of it, this sentimentality seems to be in and demonstrated a remarkable insight into conflict with the exacting academic view of the scientific value and the limits of validity of Kaischew, his strong physical and psychological the problem discussed. Even without entering into presence, the scientific erudition and strong, tight the details of some model investigation with physical argumentation during the discussions. more complex mathematics, Kaischew succeeded Simultaneously, Kaischew possessed a very to find its place in the general physical image of emotional nature and this was by far not pretended. the phenomenon and, before all, whether Being immanent to his inner world, this the results of the study are in conflict with the extraordinary sentimentality was aroused from his physical reality or the scientific paradigm. attitude toward music, mountains, skiing, nature As a result of this enormous erudition, he was and the personal life of his collaborators. The capable of formulating the scale of the mixture of academic rigor and fine, delicately investigation. In this way, the researchers could discernible emotion turns Kaischew into a build a notion about the horizon of their particular fascinating example for all his collaborators. His tasks and thus to find and enhance their own presence in the soul and being of the collaborators motivation. was evident in the everyday meetings and The formulation of the molecular theory of conversations, but exclusively in the time of the crystal growth and the following dynamic unforgettable workshops and symposia in Varna, developments at the Institute of Physical Chemistry Gyulechitsa and Pamporovo, organized have created a great reputation for Kaischew enthusiastically by all collaborators of the Institute. abroad. In 1992 on the occasion of the EWSSW Kaischew could narrate unobtrusive and captivating international conference on surface physics, interesting stories about his life as young man, his organized by the Department in Pamporovo Ski mentors and meetings with celebrated scientists, his Center, I received a letter from Sir Charles Frank travels and wanderings in Rila or Pirin mountains, (FRS), the famous Frank who created the theory of the musical analysis on Bach, Schubert, Brahms dislocation growth of crystals, where he writes: “It and Chopin, the interpretations of Glenn Gould and would give me great pleasure to participate in an Dinu Lipatti. The haughtiness of sagacity, usually event, celebrating the 85th birthday of my old emitted by the elderly was lacking in these friend, Professor Kaischew“. narrations. The respect of Frank was not only expressed in The scientific conversations with him have the words “my old friend”, it has been a respect to always been exceptionally interesting. During the Kaischew’s work together with Stranski. It can be discussion of a particular problem, Kaischew was seen in the original edition of the British Royal able intuitively to create a specific dramaturgy and Society „The Growth of Crystals and the to incite curiosity, invoked by philosophical, Equilibrium Structure of their Surfaces“, by W. K. historical and moral topics parallel with the Burton, N. Cabrera, F. C. Frank [7]. research problem. He was able to dominate, even to In this remarkable survey on more than 60 obsess the scientific imagination of the audience. pages, cited more than 5000 times in the scientific His presence in the Institute created in everybody literature, published in 1951 in Philosophical Trans- confidence and feeling of affiliation to a unique actions, only 34 fundamental studies in the field of research team, an ambiance not existing in the other crystal growth are referenced. Among these academic institutions. The members of the carefully selected papers, next to the names of Department of Phase Formation and Crystal Gibbs, Kossel, Bethe, Volmer, Onsager, Frenkel, Growth were dubbed among the colleagues Kramers, Knudsen and Max von Laue “the classicists” or “the Kaischew gang”. Kaischew are the names of Kaischew and Stranski with 34 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… their papers, published in Z. Phys. Chem. 136, 259 were already a part of the world history of phase (1928) and Z. Phys. Chem. (B) 26, 31, (1934). formation and crystal growth. With these papers, Kaischew and Stranski

A letter of Sir Charles Frank to Michail Michailov on the occasion of the 85th birthday of prof. Kaischew and his participation in the „First East-West Surface Science Workshop“, EWSSW 1994, in Pamporovo, Bulgaria, organized by the Department of Phase Formation and Crystal Growth. Between many foreign scientists and friends of Sciences “Leopoldina” from 1974 till 1990. such as the notable Max Volmer, the great Kaischew was a member of that academy since electrochemist Alexander Frumkin, the Nobel Prize 1968 and was awarded with the prestigious holder Jaroslav Heyrovsky, Peter Rebinder, the “Cothenius” medal. The Academy „Leopoldina“ encyclopedic Yakov Zeldovich, there were two was founded in 1652 and its members were Albert who have a special place in Kaischew’s heart and Einstein, Charles Darwin, Otto Hahn, Ernst played significant role in his life – Heinz Bethge Rutherford, Max Planck, etc. It was the only and Alexander Chernov. scientific institution, common for East and West Kaischew and Bethge proved to be persons of Germany at the Communism times. similar size and spirit as people and scientists. In The scientific interests and the close amity the 1980s, Heinz Bethge studies experimentally in between Kaischew and Bethge were the great detail and visualizes a number of basic background of the joint seminars, organized by the phenomena in crystal growth, including model Institute of Physical Chemistry, Sofia and the concepts of the molecular theory, by means of Institute of Electron Microscopy, Halle. These scanning, reflection and transmission electron scientific workshops organized ardently by the microscopy, (SEM and TEM) in Halle, East collaborators of both Institutes were held regularly, Germany. Particularly, the decoration with gold every three years in Halle and Gyulechitsa. Besides atoms at monoatomic steps and screw dislocation the intimate friendship between the coworkers of on the surface of sodium chloride crystals was of Kaischew and Bethge, the seminars ensured a great importance. The relation between Kaischew wonderful ambiance for social life and scientific and Bethge was particularly strong and was based discussions. Always at these meetings, the favorite not only on their personalities, but also on song of Kaischew “I’m a pirate, I’m a pirate…” significant scientific interest. Heinz Bethge was was sung traditionally by him in the company of his President of the famous German National Academy coworkers.

35 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview…

Prof. Heinz Bethge and prof. Rostislaw Kaischew. Joint seminary of the Institute of Physical Chemistry, Sofia and the Institute of Electron Microscopy, Halle, GDR in Gyulechitsa, 1987.

German-Bulgarian seminar, Gyulechitsa, 1987. The favorite song of prof. Kaischew “I’m a pirate, I’m a pirate…” From left to right: M. Michailov, S. Stoyanov, E. Mihaylov, R. Kaischew, A. Milchev, Chr. Nanev.

Remarkably close were his relations with during discussions on specific problem, even another great name in the field of nucleation without knowing the answer, to turn the discourse and crystal growth – Alexander A. Chernov. As in a direction that would get closer to that answer. a brilliant and encyclopedic scientist, Chernov In fact this is an element of the Kaischew originates from the most rigorous school in School and it is not incidentally that Chernov theoretical physics, the school of Landau and referred to Kaischew as the “Patriarch”. Since 1992 Lifshitz. Kaischew considered him as his disciple, Alexander Chernov works in the USA as a research since he had directed Chernov to join the Institute director at the most renowned American research of Crystallography at the Russian Academy of centers as NASA; George C. Marshall Space Flight Sciences and had recommended him to prof. Center, Huntsville, Alabama; Lawrence Livermore Shubnikov who headed the Institute at that time. In and Lawrence Berkeley National Laboratories, the following years, Chernov achieved an California. outstanding scientific career in the fields of In the 1990s and the beginning of the new thermodynamics and kinetics of nucleation, century, Kaischew is the main person that attracts a morphological instability and kinetic coefficients in number of renowned scientists in condensed matter crystal growth, computer modelling, crystallization physics to influential international scientific of proteins and biological minerals. An exceptional forums, organized by the Institute of Physical quality of prof. Chernov was his capability Chemistry.

36 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview…

Prof. Alexander Chernov and prof. Rostislaw Kaischew. The so-called “Stranski-Kaischew” conferences (Maryland, USA), Doon Gibbs (Berkley, USA), in Bulgaria bring together leading world scientists Alexander Chernov (NASA; George C. Marshall in the field of surface physics and crystal growth. Space Flight Center, Alabama, USA), Raymond Among the regular lecturers and participants are Kern (Marseille, France), Matias Scheffler (Max David Landau (Georgia, USA), Kurt Binder Planck Institute, Berlin, Germany), Martin Henzler (Mainz, Germany), Robert Sekerka (Carnegie (Hanover, Germany), Ellen Williams (Maryland, Melon, Pittsburg, USA), Boyan Mutaftchiev (Paris, USA), Erio Tosatti (Trieste, Italy), Harald Ibach France), Kenneth Jackson (Arizona, USA), Joost (Jülich, Germany), Harald Brune (Lausanne, Frenken (Leiden, Holland), Theodor Einstein Switzerland).

Prof. David Landau, Georgia University and prof. Theodor Einstein, Maryland University at the third „Stranski-Kaischew” Workshop in Surface Science, SKSSW 2005, Pamporovo, Bulgaria.. Particularly impressive was the scientific positions in the monoatomic steps. Kaischew, who workshop “EWSSW 94” in Bulgaria, at which was 86 at the time, deeply moved during the lecture Joost Frenken from Leiden University in Holland said: “I have never imagined that in my live I demonstrated for the first time the diffusion would see with my eyes a direct experimental proof dynamics of individual metal atoms in the vicinity of our notion with Stranski about the mechanism of of monoatomic steps on crystal surfaces. The crystal growth. Despite of its simplicity, our model brilliant experiment performed by high temperature created in 1934 seems to be true”. Here, a general scanning tunneling microscopy (STM) revealed that distinctive characteristic of the scientific ideas of growth and dissolution of crystals is indeed Stranski and Kaischew, developed in the classical accomplished by attachment and detachment of molecular theory of phase formation and crystal individual atoms at the theoretically predicted kink growth, is emphasized. It is their simplicity.

37 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview…

Prof. Kaischew at the Workshop in Pamporovo, 1994, devoted to his 85 anniversary (left). Prof. Robert F. Sekerka (left), Carnegie Melon University and prof. Kenneth A. Jackson, University of Arizona, lecturers at the same conference (right). These notions follow elegantly the concept of be famous). He used to say to his collaborators and Karl Popper about the substance of science and students that “science is made with worn out pants” scientific theories stating that “The methods of and that was no airs and graces. The ambiance of scientific knowledge are related to our attempts to his home was build up by the music of Bach, describe the world by means of simple theories. Brahms and Schubert, Vihren mountain peak and The complex theories may fail to be proved even Vasilashki lakes in Pirin, the beautiful when they turn to be true. The science itself may be Chokmanovo in Rhodope, the moderate sadness described as the art of systematic simplification – and nostalgia for the old Europe, the restrained, the art to discern what can be initially excluded“. self-controled indignation to the communist regime. To the end of his life, Kaischew remained a This way of life was amazingly shared by the classical university professor and scientist, keeping qualities and values of his wife, Milka Kaischewa, the academic tradition in its genuine style, namely an extremely cordial, fine and highly educated searching and trying to understand the general woman, daughter of the famous Bulgarian regularities and the fundamental reasons for the mathematician, Lubomir Chakalov, Member of the processes and phenomena in Nature. He succeeded Academy. Mrs. Kaischewa dedicated her entire life throughout the years to avoid vanity and popularity wholeheartedly and delicately to create calmness, of speculative, unprincipled attractive study that placidity, silence and warmth for her husband, brings fast but evanescent fame just because of the consecrated and ardent to science. lack of scientific depth and meaning. For Kaischew Rostislaw Kaischew was the last person of the the understanding, assembling and spreading outstanding generation of the „Great Masters“ W. fundamental scientific knowledge was much more Kossel, I. Stranski, M. Volmer and F. Frank who significant than the loud engagement in modern, laid the foundations of the modern theory of crystal technologically oriented projects which bring growth. He knew to the end of his life what he attractive financing. He had no taste for monetary leaves behind, and this was not only the success and luxury, lived modestly and did not care contribution to the theory of phase formation and for the banal socialists’ living standards – lodging, crystal growth. Kaischew left a scientific school car, country house. He was probably the only and through it – respect, disciples, friendship, Member of the Academy who did not possess a devotion, scientific standards, style of research and summerhouse. The personal life of Kaischew academic dignity. All of this under the rule of a followed largely the excellent verse by Pasternak - communist regime, at a time inauspicious for the „Быть знаменитым, некрасиво“ (it is not lovely to footloose investigating spirit. Nevertheless, he 38 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… succeeded to conserve the meaningful and to The author is thankful to Willy Obretenov for decline cleverly the commonplace and mediocre. valuable help throughout the preparation of the Kaischew was not merely a scientist, he was an English version of the manuscript. institution. Together with Iwan Stranski, he left one ------of the few uncontestable, substantial Bulgarian contributions to the world scientific history of Academic ranks and grades of prof. Rostislaw mankind. Kaischew Each scientific school has its own glorious rise Doctor, 1932, Breslau University, Germany. and inevitable fall. The dynamics of these rises and Assistant, 1933, Department of Physics and falls is determined not only by the unavoidable Mathematics, University of Sofia. drama of the particular scientific paradigm, but also Docent, 1944, (private docent since 1941), by the dominating values of the time of its Department of Physics and Mathematics, existence. During the last two decades, the science University of Sofia. and research in Bulgaria are rather subject to Professor, 1947, Department of Physics and Caesar’s rules (Matthew 22:15-22), than to the Mathematics, University of Sofia Corresponding classical genuine moral, ethic and academic values. Member of BAS, 1947. Nowadays, the dominating aims of knowledge are Full Member (Academician) of the Bulgarian cynically utilitarian, technologically oriented and Academy of Sciences, 1961. directed toward consumerist society. The science increasingly serves technologies of wealth and Leading positions of prof. Rostislav Kaischew pleasure. This is a metaphysical, fundametal Head of Chair “Physical Chemistry”, University of contradiction with the genuine meaning of the Sofia, 1944-1966. human knowledge, trying to find the place of man Dean of the Department of Physics and in the architecture and ordering of the world, in its Mathematics, University of Sofia, 1955-1956. wonderful structure, logic and aesthetics. Possibly, Director of the Institute of Physical Chemistry, because of that the contemporary scientific schools BAS, 1958-1989. cannot exist in their classical form anymore. They Secretary to the Section of Chemical Sciences of are rather high-tech engineering centers, founded BAS, 1961. and developed by economic and financial reasons Vice-President of the Bulgarian Academy of and interests. At the present time, science and Sciences, 1961-1968. research are motivated by the usefulness and not by knowledge. „Gaudeamus igitur, vivat academia, Membership of prof. Rostislaw Kaischew in vivant professores“ turn to emotional, historical international scientific institutions mental impressions, memories, retrospections Member of the German Academy of Sciences, carrying the nucleus of knowledge, but ineligible 1957. and eliminated in the name of the benefit. This is Member of the Czech Academy of Sciences, 1966. the fate of the famous Stranski-Kaischew Sofia Member of the Saxon Academy of Sciences, 1968. School of crystal growth, too. It was however, a Member of the German National Academy of remarkable intellectual phenomenon during the Sciences “Leopoldina”, 1968. twentieth century and its existence, success and Vice-President of the International Union of Pure resplendency give moral and cognitive sense to and Applied Physics, 1975-1980. many people, particularly to that not tempted by vanity, lucre and riches, sentimental and worthy Government and academic awards of prof. research academic community in Bulgaria, for Rostislaw Kaischew which, as stated in the widely held Bulgarian Grand gold sign of honor for merits to Austrian anthem of knowledge, „science is a sun shining Republic, 1983. within the souls“ or, as it sounds in Bulgarian, “Cothenius” gold medal of the German National „науката е слънце, което в душите грей”. Academy of Sciences “Leopoldina”, 1987. Acknowledgment: The present paper is a Order ”Cyril and Methodius” – I grade, 1958, 1963. modified translated edition of the review chapter Sign of honor from the city of Sofia, 1978. devoted to prof. Rostislaw Kaischew and Sofia Sign of honor from the University of Sofia, 1988, school of crystal growth in the forthcoming book 1998. celebrating 90 years of the Physical Chemistry Sign of honor “Marin Drinov” from the Bulgarian science in Bulgaria; Prof. M. Drinov Publishing Academy of Sciences, 1999. House, Sofia (in press). 39 M. Michailov: Rostislaw Kaischew and his trace in the fundamental science. A brief historical overview… Honorary Member of the Bulgarian Academy of 20. R. Kaischew, I. N. Stranski, Zur Theorie der linearen Sciences, 2002. Kristalisationsgeschwindigkeit, Z. phys. Chem. A, 170, 295 (1934). REFERENCES 21. I. N. Stranski, R. Kaischew, Über den Mechanismus des Gleichgewichtes kleiner Kristallchen I, Z. phys. 1.R. Kaischew, On the history of the creation of the Chem. 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РОСТИСЛАВ КАИШЕВ И НЕГОВАТА СЛЕДА ВЪВ ФУНДАМЕНТАЛНАТА НАУКА. КРАТЪК ИСТОРИЧЕСКИ ОБЗОР М. Михайлов Институт по физикохимия "Академик Ростислав Каишев", Българска академия на науките, ул. "Акад. Г. Бончев", бл. 11, София 1113, България