Joan Henri van der Waals

Joan Henri van der Waals (2 May 1920 – 21 June 2022) was a Dutch physicist. He was professor of experimental physics at Leiden University between 1967 and 1989. He specialized in molecular physics and clathrate hydrates. One of Van der Waals's most significant contributions to the study of hydrates was a series of papers between 1953 and 1958, which eventually culminated in the 1959 publication of his paper on the canonical partition function for clathrates, along with J. C. Platteeuw. To create this partition function, van der Waals made a number of simplifying assumptions, most prominently that neighboring guest gas molecules cannot interact and there is a maximum of one guest per cage.

Early life Van der Waals was born on 2 May 1920 in Amsterdam. A book on the Bohr model sparked his interest in physics. In 1942, Van der Waals completed the long-distance tour-skating event, the Elfstedentocht. Van der Waals was elected a member of the Royal Netherlands Academy of Arts and Sciences (KNAW) in 1971. He served on the board of the KNAW between 1984 and 1987. He has been an honorary member of the Royal Netherlands Chemical Society since 1998. Van der Waals was appointed Knight in the Order of the Netherlands Lion.

Van der Waals has been involved in the conservation and restoration of the Trippenhuis, the seat of the KNAW, since the 1980s. Van der Waals was the first cousin, twice removed, of Dutch Nobel Prize–winning physicist Johannes Diderik van der Waals. and died on 21 June 2022, at the age of 102.