Professor Timothy Schmidt from the ARC Centre of Excellence in Exciton Science
Original Published Date: 
Tuesday, March 10, 2020

Full article issued by the ARC Centre of Excellence in Exciton Science.

One of the fundamental mysteries of chemistry has been solved by a collaboration between the ARC Centre of Excellence in Exciton Science, The University of New South Wales (UNSW) and the CSIRO—and the result may have implications for future designs of solar cells, organic light-emitting diodes and other next-gen technologies.

Ever since the 1930's, debate has raged inside chemistry circles concerning the fundamental electronic structure of benzene, an organic chemical compound which is a component of DNA, proteins, wood and petroleum. The debate has in recent years taken on added urgency, because benzene—which comprises a flat hexagonal ring of six carbon atoms matched with six hydrogen atoms—is the fundamental building-block of many opto-electronic materials, which are revolutionising renewable energy and telecommunications technology.

Now researchers, led by ARC Future Fellowship recipient, Timothy Schmidt from the ARC Centre of Excellence in Exciton Science, and UNSW Sydney, have succeeded in unravelling the mystery—and the results were unexpected. 

“What we found was very surprising,” said Professor Schmidt. “The electrons with what’s known as up-spin double-bonded, where those with down-spin single-bonded, and vice versa.  

Professor Schmidt, with colleagues from UNSW and CSIRO’s Data61, applied a complex algorithm-based method called dynamic Voronoi Metropolis sampling to benzene molecules in order to map their wavefunctions across all 126 dimensions. The method allowed the partition of the dimensional space into equivalent 'tiles', each corresponding to a permutation of electron positions.

As well as resolving the mystery of the electronic structure of benzene, the researchers say that the algorithm can be applied to other problems of 'matching with constraints' such as staff rostering and kidney exchange programs.

Photo credit: 

Professor Timothy Schmidt from the ARC Centre of Excellence in Exciton Science, unravelling the mystery of benzene. Credit: ARC Centre of Excellence in Exciton Science.