History and Background

Aperiodic crystals are long-range ordered structure that lacks periodicity in at least one dimension and are encountered in a large variety of compounds from single elements under pressure to soft condensed matter or proteins. Professor Ted Janssen (1936-2017) and Professor An-Pang Tsai (1958-2019) have been two of the most outstanding scientists pioneering the field of aperiodic crystals. Professor Ted Janssen co-invented the concept of superspace crystallography, a very elegant approach which allows to solve the structure of aperiodic crystals by recovering a periodic description in a space with more than three dimensions. He also made major contributions in the understanding of the dynamics of aperiodic crystals and in particular for long wavelength fluctuation named phason modes. An-Pang Tsai has discovered most of the intermetallic stable quasicrystals studied by the community, using a specifically designed Hume-Rothery rule as a guiding principle. He was involved in most of the important experimental discoveries in this field. He also opened new routes in view of applications for structural materials and more recently for catalysis.

Both of them were very accessible, always keen and enthusiastic to share their knowledge with young scientists. They had a key impact in structuring the community.

In their memory the Commission on Aperiodic Crystals of the IUCr has implemented the Ted Janssen and An-Pang Tsai Prize in 2024.

Nomination

The Ted Janssen and An-Pang Tsai prize recognizes an outstanding contribution to the field of Aperiodic Crystals, from theory to applications.  The nominee must be under 45 years of age at the time of the submission deadline. The winner(s) will receive a certificate and will be invited to deliver a talk at the triennial Aperiodic Conference. The nominee must be under 45 years of age at the time of the submission deadline*. 

The nomination must be sent to aperiodic2024@sciencesconf.org with the subject "Janssen-Tsai prize" before April 15 2024 and contain the following document:  

• A letter of not more than 3000 characters evaluating the nominee's qualifications in the field of aperiodic crystals and identifying the specific work to be recognized. There is no nomination form, so this letter is considered the nomination "application".
• Curriculum vitae of the nominee.
• A list of the most important publications of the nominee.

* The nominee age limit is extended by one year for each maternity leave.