1963-1967: a crystallographic thesis for Chemistry degree

by Angelo Gavezzotti

This contribution tells the story of an undergraduate student at the University of Milano, who started his thesis in 1967 on the determination of the crystal structure of an aromatic hydrocarbon molecule. The story starts with Weissenberg machines, proceeds through an unreliable automated diffractometer and a re-determination of diffracted intensities by visual integration of spots on films, continuing with the exertions on a mythic IBM 1620 computer which could hold no more than 7,500 numbers or instructions in its ferrite-ring memory. The happy ending, one year later, is the description of the haphazard use of direct methods by a computer program originating from Bob Long, David Sayre and Kenny Trueblood, which produced the correct phases as no one expected it would. The story makes great didactic and perspective material for present-day students who manage to do the same whole job in one afternoon. For those who are less familiar with Italian, the same story is told in English in Chapter 5 of the book: A.Gavezzotti, Molecular aggregation, Oxford University Press, 2007