Knowledge Bank

The first rotationally-resolved spectrum of a van der Waals complex formed between two chiral molecules will be presented. The complex is a hetero-chiral dimer of butan-2-ol and the spectrum was observed by Fourier Transform Microwave Spectroscopy in a supersonic $expansiona$. The results of the ab initio calculations used to identify the dimer will also be presented. The microwave spectrum of a complex formed between a butan-2-ol molecule and an argon atom will also be discussed, including a limited amount of structural $analysisb$. This too will be accompanied by an ab initio study. Finally, mention will be made of the detection of six of the nine possible conformational isomers of the butan-2-ol molecule in expansions of argon and $heliumc$. There are still a large number of unassigned lines in the spectrum of butan-2-ol, some of which must be due to the homo-chiral dimer. Work to assign them is ongoing, any new results will be presented.