Tributes paid to Dr Ian McDonald

Trinity colleagues have paid tribute to the chemist, Dr Ian McDonald (1938-2020), who died on 19 July 2020.

Dr McDonald came from Royal Holloway College in 1979 to be a Teaching Fellow in Theoretical Chemistry at Trinity and Lecturer at the Chemistry Department at Cambridge.

Trinity Fellow and Professor of Chemical Physics, Stephen Elliott, said: ‘Ian was one of the first of a series of faculty members, all trained as physicists, recruited by the Department to teach Theoretical or Physical Chemistry. He gained international renown for his pioneering work on the computer simulation of materials, especially liquids.’

In 1976 Dr McDonald published the first edition of the textbook, Theory of Simple Liquids, with his long-standing collaborator, Jean-Pierre Hansen, who went on to become Professor of Theoretical Chemistry in the Department at Cambridge. The seminal textbook went through four editions, the last appearing in 2013.

Professor Elliott recalls Dr McDonald’s ‘old school’ characteristics: self-effacing and generous.

Ian was an extremely self-effacing person, and “very much of the old school (in the nicest possible way),” as the current Head of the Chemistry Department, Dr James Keeler, has noted. Ian was always very generous with his time and advice to everyone. I much appreciated this when I was appointed to be his colleague, the Teaching Fellow in Physical Chemistry, two years after he arrived here.

Ali Alavi was a Trinity undergraduate and research student of Dr McDonald, and later his successor as Teaching Fellow in Theoretical Chemistry. Now Professor of Theoretical Chemistry at Cambridge and Director of the Max Planck Institute for Solid State Research in Stuttgart, Professor Alavi paid tribute to Dr McDonald’s meticulousness in the quest for ‘utmost clarity.’

We have lost a meticulous teacher and scientist, one who never sought the limelight, but nevertheless ensured that the science that he was involved in would always be presented with the utmost clarity.

Apart from his pioneering work in developing methods for atomistic simulation, Ian McDonald had a uniquely clear style of writing and exposition. Any draft of a paper submitted to him by his co-authors (no matter whom, from research student to famous professor), would be returned within a few days almost entirely rewritten, with the logical train of thought clearly exposed. No sentence that contained ambiguity would pass his notice.

As a result his papers (and of course his classic textbook) are considered to be absolute models of clarity. Similarly, his lecture notes in Statistical Thermodynamics, which he wrote in the 1990s, are still used today in the Chemistry Natural Sciences Tripos for much the same reason: he took what was considered by undergraduates to be a notoriously difficult subject, and clearly exposed its concepts.

Professor of Theoretical Chemistry at Cambridge and Trinity Honorary Fellow, Daan Frenkel, remembers the modesty of Dr McDonald and Professor Konrad Singer, with whom he pioneered the use of computer simulations in physical chemistry at Royal Holloway College in the 1960s.

As a postdoc with Konrad, Ian started to perform Monte Carlo and Molecular Dynamics simulations and, starting in 1967, published a number of seminal (and still widely cited) papers on the topic. It should be stressed that Ian and Konrad were the first scientists in the UK to explore molecular simulations – but both were modest men. For scientists outside the Cambridge system it was very hard to understand that Ian, an international star, retired as a lecturer.

In addition to serving as Editor of the scientific journal, Molecular Physics, Dr McDonald was Admissions Tutor at Trinity, 1994-2002. Trinity Fellow, Dr Paul Wingfield, took over the role from Dr McDonald in 2002. ‘Ian was a great help to me when I first took on the role. Admissions Tutor is a key role in College with many moving parts and a lot of complex information. Without Ian’s assistance, I would have found it much harder to get to grips with the job,’ Dr Wingfield said.