Probing the structure and dynamics of molecular complexes using rotational wavepackets
Résumé
Rotational wave packets of the weakly bound C2H2-He complex have been created using impulsive
alignment. The coherent rotational dynamics were monitored for 600 ps enabling extraction of a frequency
spectrum showing multiple rotational energy levels up to J ¼ 4. spectrum has been combined with
ab initio calculations to show that the complex has a highly delocalized structure and is bound only by ca.
7 cm−1. The experiments demonstrate how highly featured rotational spectra can be obtained from an
extremely cold environment where only the lowest rotational energy states are initially populated.