CHAPTER 4 The Development of Computational Chemistry in Canada Russell J. Boyd Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 413 INTRODUCTION The development of computational chemistry in Canada is inextricably linked with the emergence of theoretical chemistry as one of Canada’s strongest scientific disciplines. For this reason, the present account chronicles the history of both computational and theoretical chemistry in Canada. The first theoretical chemists were appointed to Canadian universities in the mid- to late 1950s, long after strong traditions for theoretical chemistry had been established in Europe, the United Kingdom and the United States. Further- more, many of the first Canadian theoreticians often carried out experiments or maintained experimental laboratories in departments of chemistry in which the dominant figures were typically experimental physical chemists or organic che- mists with a penchant for natural products and synthesis. The late development of theoretical chemistry in Canada was a conse- quence of the relatively weak research base in Canadian universities prior to 1950. In fact, research in Canadian universities during the first half of the twentieth century lagged seriously behind that of the leading universities of the major industrialized nations. Only McGill University and the University of Reviews in Computational Chemistry, Volume 15 Kenny B. Lipkowitz and Donald B. Boyd, Editors Wiley-VCH, John Wiley and Sons, Inc., New York, 0 2000 213 21 4 The Development of Computational Chemistry in Canada Toronto had gained international reputations as major research institutions before the Second World War. Although some research was carried out prior to 1950 at about 20 universities across Canada, the majority of the significant research was done in the laboratories of the National Research Council of Canada (NRC) in Ottawa. From its humble beginnings in 1916, the NRC developed into a research organization which by the 1960s operated some of the premier research laboratories in the world. Long before Canada developed a reputation in theoretical and computa- tional chemistry, the one Canadian scientist who needed no introduction was Gerhard Herzberg. His book on atomic structure1 was known to many genera- tions of chemistry students, and his book on diatomic molecules2 and the later one on polyatomic molecules” became standard references for theoretical che- mists worldwide. Herzberg was born in Hamburg, Germany, on December 25, 1904 and died in Ottawa on March 3, 1999. After earning his doctorate in engineering physics from the Technical University of Darmstadt in 1928, he did postdoc- toral research at the universities of Gottingen and Bristol. In 1930 he returned to Darmstadt and during the next five years his research in atomic and molecu- lar spectroscopy flourished. As his scientific reputation was growing, he re- ceived an invitation from Dr. J. W. J. Spinks to join the Department of Physics at the University of Saskatchewan. During his 10 years in Saskatoon he made major applications of spectroscopy to physics and chemistry. In 1945 he was appointed professor of spectroscopy at the Yerkes Observatory of the Univer- sity of Chicago. After three years in the United States, Herzberg returned to Canada to take up a position at the National Research Council laboratories in Ottawa. When he was awarded the Nobel Prize in chemistry in 1971, the citation stated, Dr. Herzberg is generally considered to be the world’s foremost molecular spectroscopist, and his large institute in Ottawa is the undisputed centre for such research. In 1994 on the occasion of Herzberg’s ninetieth birthday, the Canadian Journal of Physics published a special issue. The festschrift, edited by Donald Betts and John Coxon of Dalhousie University, contains 72 papers by many of the world’s leading spectroscopists and theoretical chemists. In his acknowledg- ment, Nobel laureate Dudley Herschbach summarized Herzberg’s inestimable impact with the following tribute? With pleasure we dedicate this paper to Gerhard Herzberg. For us, as for a host of others, he has through his books served as a superb, inspiring mentor. As well as showing us the exhilarating scope of spectroscopic methods, he has taught us to orient our work toward basic questions and Introduction 2 15 to strive for treatments that take account of complications as simply as possible. An article entitled simply “G. H.” by Boris Stoicheff is recommended to those who are interested in learning more about Herzberg’s remarkable career and scientific achievements. Stoicheff’s article appeared in the April 1972 spe- cial issue of Physics in Canada, published in honor of Gerhard Herzberg on the occasion of his receipt of the Nobel Prize. Another landmark in the history of theoretical chemistry in Canada per- tained to funding. To stimulate research in Canadian universities, the NRC established a grants program and awarded research grants on a competitive basis to university researchers. During his presidency (1952-1962), E. W. R. Steacie established the principle that NRC’s extramural budgets for grants and fellowships should rise to match the intramural budget ($215 million in 1962- 1963). Ultimately the NRC was in the difficult position of having to choose between funding its own laboratories and the peer-reviewed applications from external (university) researchers. To alleviate this conflict of interest, the Cana- dian government transferred in 1978 the research grants and scholarships pro- grams of the NRC to a new federal granting agency, the Natural Sciences and Engineering Research Council of Canada (NSERC). Research in Canadian universities expanded rapidly in the 1960s for sev- eral reasons. The launching of Sputnik in 1957 by the Soviet Union shocked the Western nations and led to a rapid expansion of the existing universities and the creation of many more. Consequently, funding for research grew dramatically, many young people (including the author) were attracted to science, and univer- sities started to put more emphasis on research. The number of universities offering the Ph.D. degree in science increased from 2 in 1940 to more than 25 in 1970. With this brief introduction, it is useful to reflect on the state of the development of theoretical chemistry in 1970, little more than a decade after its establishment in Canadian universities. In 1970 on the occasion of its twenty-fifth anniversary, The Chemical Institute of Canada published a 290-page book entitled Chemical Canada. The authors intended the book “to present a general account of the impact of things chemical in Canada up to, and including, the present time.” The book consists of three parts, the third part being a 50-page summary of research and develop- ment in Canada. The R&D section is organized by topics and devotes only two short paragraphs to theoretical chemistry. These two paragraphs are repro- duced here for their interesting historical perspective.5 The very rapid increase in the number of theoretical chemists in Canada since 1962 does not reflect the true growth rate, or one which can be expected to continue; the sudden increase in numbers was caused by many 21 6 The Development of Computational Chemistry in Canada universities hiring their first theoretician. Although there has been a marked reluctance in many chemistry departments to consider theoretical chemistry as a discipline in itself, worthy of being pursued for its own sake, about eight departments having one theoretician have plans to hire another in the near future, and two departments have initiated plans to form centers of theoretical research consisting of about six staff members. The solution to the problems involved in the theoretical study of the electronic structure of large molecules and reaction rate theory demands very large and very fast computers, larger and faster than those now available in Canada. If these studies are to proceed, greatly expanded computing facilities must be made available. The type of computer envis- aged and necessary for these calculations would be of such a large size that Canada could afford only one or two such installations. It is a general feeling that by the establishment of such a central computational facility, Canada could, for a nominal amount, be in the forefront of a number of critical areas in scientific research and development. The data collected for the 1970 chapter support the authors’ statements and their prophetic predictions. Moreover, their comments about computing facilities are still relevant, three decades later. IN THE BEGINNING THERE WAS QUANTUM CHEMISTRY AND SPECTROSCOPY The early efforts in quantum chemistry in Canada, as in other countries, were closely connected with electronic spectroscopy. Later the scope expanded to include all forms of spectroscopy. One of the Canadian pioneers whose interests epitomize the history of quantum chemistry is Camille Sandorfy. After graduating from the University of Szeged in his native Hungary and completing a D.Sc. under the supervision of Profs. Louis de Broglie and R. Daudel at the Sorbonne in Paris, Sandorfy took up a postdoctoral fellowship with Dr. R. Norman Jones, a spectroscopist at the National Research Council of Canada laboratories in Ottawa. By the end of 1953, Sandorfy had settled in Montreal, where he began a highly distinguished career, initially as a theoretical chemist and ultimately as a full-time spectroscopist, specializing in the far-ultraviolet and infrared regions. He developed the basis for a very strong group in quantum chemistry that continued to flourish under the leadership of Dennis Salahub and his younger colleagues at the University of Montreal. In the years 1945-1955 theoretical chemists as well as chemical spec- troscopists concentrated their efforts on systems containing n: electrons. Such In The Beginning There Was Quantum Chemistvy and Spectroscopy 21 7 molecules can be easily treated by simple molecular orbital methods. It was considered a normal procedure in those times to treat the n electrons as a separate quantum chemical problem to which the (J electrons supply a sup- posedly uniform potential field.