Chapter 8 Quantum Chemistry Program Exchange, Facilitator of Theoretical and Computational Chemistry in Pre-Internet History Donald B. Boyd* Department of Chemistry and Chemical Biology, School of Science, Indiana University – Purdue University Indianapolis (IUPUI), 402 North Blackford Street, Indianapolis, Indiana 46202-3274 *E-mail: [email protected] The Quantum Chemistry Program Exchange (QCPE) was a service conceived in 1962 and that started operating in 1963. Its purpose was to provide an inexpensive mechanism for theoretical chemists and other scientists to exchange software. Most of the computer programs were distributed as source code, so scientists, if they wanted to, could learn from or improve upon the inner workings of the algorithms. QCPE reached its zenith in the 1980s when computational chemistry was growing rapidly and becoming widely recognized by the scientific community. The service was convenient and much used by experts, students, and experimentalists who wanted to perform research calculations in the study of molecules. QCPE Publication Date (Web): February 13, 2013 | doi: 10.1021/bk-2013-1122.ch008 also played an educational role by conducting workshops and Downloaded by RADBOUD UNIV NIJMEGEN on May 4, 2018 | https://pubs.acs.org providing on-call help to countless beginners. QCPE was based at Indiana University in Bloomington, Indiana, and serviced a worldwide clientele. Introduction of the Internet in the 1990s diminished the role of QCPE. Introduction As the name implies, the Quantum Chemistry Program Exchange (QCPE) started with the purpose of being a distribution hub for software tools used by quantum chemists. QCPE was a great boon to theoretical and other chemists as the field of computational chemistry developed in the 1970s and 1980s. QCPE © 2013 American Chemical Society Strom and Wilson; Pioneers of Quantum Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 2013. started operations in 1963 and served a vital function during its lifetime. Most of the leading names in theoretical chemistry – and later computational chemistry – joined QCPE because it provided a service in high demand. Unlike most commercial software companies, QCPE expedited science by distributing source code at nominal cost and providing free guidance to users. But by the first decade of the 21st century, the service had done its duty and most of its functions had ceased or were winding down. Most of the individuals involved with QCPE’s creation and operation are unfortunately getting to the point where the patina of maturity is turning to the rust of old age. This situation increases the urgency of writing this chapter now. Much of the original documentation related to QCPE has been digitized or discarded or is in private collections. This historical account is based partly on personal recollections (however faulty they may be) and partly on records and old QCPE publications. These resources have been substantially supplemented with recent e-mail correspondence and interviews with some of the key players. In one or two cases, different people had differing recollections, so the author tried to steer toward a middle ground of what may have happened. The author has tried to be as accurate as possible, given the circumstances. This is a story that has an abundance of heroes and no “bad guys”. The author also presents previously unpublished photographs of historical interest. QCPE is a case that illustrates that if individuals with initiative set out to perform a needed function, there are many rewards. The author published a Reader’s Digest-version of the history of QCPE in 2000 (1). The important role of QCPE was also discussed in a 2007 book (2). A Stellar Idea The older readers of this chapter will remember QCPE and may have used its services, but some of our younger readers may never have heard of this service. So our narrative begins at the beginning. QCPE was founded at the inspiration of Professor Harrison G. (“Harry”) Shull, a quantum theoretician and research professor at Indiana University, Bloomington (IUB) in the years1955-1979 (Figure Publication Date (Web): February 13, 2013 | doi: 10.1021/bk-2013-1122.ch008 1). He had obtained his baccalaureate degree from Princeton in 1943 and earned Downloaded by RADBOUD UNIV NIJMEGEN on May 4, 2018 | https://pubs.acs.org his doctorate in physical chemistry at the University of California, Berkeley in 1948. Shull has been described as the sort of person from whom ideas bubbled forth. He was good at team building. He had a knack for inspiring people around him to gladly work on his ideas. Shull did not mind letting his associates get credit for the achievements they accomplished. Shull chaired a Gordon Conference on Theoretical Chemistry in the summer of 1962. This gathering was attended by two future winners of the Nobel Prize in Chemistry: Robert Sanderson Mulliken (University of Chicago), who won in 1966, and John Anthony Pople (National Physical Laboratory, Teddington, England), who won in 1998. As expected, most of the theoreticians at the conference were from academia, but even back in 1962, a few of them were from industry. American companies, even back in the 1960s, recognized the value of theoretically and computationally trained chemists (3). 222 Strom and Wilson; Pioneers of Quantum Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 2013. Figure 1. Professor Harrison G. Shull in the late 1950s or early 1960s. The photograph is courtesy of Judi Roberts and Roger Beckman of the Indiana University staff. Shull’s vision was to have a central, international, sharable repository of software available to quantum chemists. At the conference, Professor Stanley A. Hagstrom (Figure 2) chaired a session on software sharing. Hagstrom was an IUB assistant professor of chemistry who had obtained two bachelor degrees from the Publication Date (Web): February 13, 2013 | doi: 10.1021/bk-2013-1122.ch008 University of Omaha and in 1957 a Ph.D. degree in theoretical chemistry under Downloaded by RADBOUD UNIV NIJMEGEN on May 4, 2018 | https://pubs.acs.org Shull at what is now called Iowa State University. Already, Professor Clemens C. J. Roothaan at the University of Chicago had set up a registry and exchange for two-electron integrals. So, there was precedence for avoiding tedious duplication of effort. Many theoreticians could see the advantage of exchanging computer programs. It was inefficient for graduate students at one university to have to write a program to do the same quantum mechanical calculations that had already been programmed elsewhere. It made sense to have these widely needed programs available in order to avoid “reinvention of the wheel”, as it were. A second motivation for setting up a library of shared software was to create a more or less permanent repository. So, if a graduate student finished a thesis and left a university, or if a professor changed research interests, the fruits of their labors - in terms of software written - would not be lost or lie unused on some dusty shelf or in a forgotten cabinet. 223 Strom and Wilson; Pioneers of Quantum Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 2013. Figure 2. Professor Stanley A. Hagstrom in the late 1950s or early 1960s. The photograph is courtesy of Judi Roberts and Roger Beckman of the Indiana University staff. A third motivation for a central repository was to create an intermediary between the code writers/owners and users. Quantum chemistry professors whose students had created useful programs could directly share copies with other research groups. However, the users in the other groups might not understand all the requirements of operation or the limitations for getting useful results. The new program might be minimally or unclearly documented. Hence these users would frequently be asking the developers for help. For widely used programs, Publication Date (Web): February 13, 2013 | doi: 10.1021/bk-2013-1122.ch008 such requests could consume time and distract the original developers from Downloaded by RADBOUD UNIV NIJMEGEN on May 4, 2018 | https://pubs.acs.org other work. So, someone at a central depository could field at least some of these routine questions from the users, thereby freeing the developers from being badgered for technical support. There was a fourth motivation. Depositing programs with QCPE could be regarded as a form of “publishing” the code. Recall that back in the 1960s, there were few or no means of publishing codes in the vetted scientific literature. In this regard, academic traditionalists were just beginning to think about the fact that creating a significant computer code was, in effect, a form of intellectual writing. At the Gordon Conference, there was sufficient interest in having a central repository for exchanging programs, so when Shull returned to Bloomington, Indiana, he recruited his postdoctoral associate from England, Dr. Keith M. Howell (Figure 3), to set up the exchange. Howell had graduated from Bristol University (England) in 1952 and crossed the Atlantic to work with Hagstrom at 224 Strom and Wilson; Pioneers of Quantum Chemistry ACS Symposium Series; American Chemical Society: Washington, DC, 2013. IUB in 1956, first on a card-programmed calculator and then on an IBM 650 with magnetic drum storage. After gaining his Ph.D. at Southampton University in 1960, he worked in industry before sailing back to the United States in October 1962 with his bride. Shull gave Howell carte blanche to set up QCPE. The initial effort was partially supported by the Air Force Office of Aerospace Research (ARAC) and Indiana University. Howell developed the initial mechanics for submitting, testing, and distributing software in collaboration with Hagstrom and Dr. Franklin (Frank) Prosser, another member of Shull’s group. Prosser had obtained two degrees at Georgia Institute of Technology and then a Ph.D. at The Pennsylvania State University. The fact that Hagstrom and Prosser had part-time appointments in the IUB Computing Center greatly facilitated this activity.