Probing the structure and dynamics of molecular clusters using rotational wave packets.

Gediminas Galinis,I C Edmond Turcu,Mirjana Mladenović,Marius Lewerenz,Russell S Minns,Arnaud Rouzée,Richard T Chapman,Luis G Mendoza Luna,Cephise Cacho,Mark J Watkins,Emma Springate,Klaus Von Haeften,Andrew M Ellis

doi:10.1103/physrevlett.113.043004

Abstract

Rotational wave packets of the weakly bound C(2)H(2)-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 = 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.

Highlights

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 1⁄4 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 weak binding leads to large amplitude motion and delocalized structures that are often reflected in complex rotational spectra that cannot be categorized through rigid rotor models

Summary

Introduction

Rotational wave packets of the weakly bound C2H2-He complex have been created using impulsive alignment. Frequency-domain spectra of molecules embedded into large superfluid helium droplets show sharp rotational transitions, suggesting that wave packets will not dephase [2,13].

Results

Conclusion