Rotational echoes as a tool for investigating ultrafast collisional dynamics of molecules

H. Zhang (1) , B. Lavorel (1) , F. Billard (1) , J.-M. Hartmann (2) , E. Hertz (1) , O. Faucher (1) , Junyang Ma (3, 1) , Jian Wu (3) , Erez Gershnabel (4) , Yehiam Prior (4, 3) , Ilya Sh. Averbukh (4)

1 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
2 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
3 State Key Laboratory of Precision Spectroscopy
4 The Weizmann Institute of Science

We show that recently discovered rotational echoes of molecules provide an efficient tool for studying collisional molecular dynamics in high-pressure gases. Our study demonstrates that rotational echoes enable the observation of extremely fast collisional dissipation, at time scales of the order of few picoseconds, and possibly shorter. The decay of the rotational alignment echoes in CO2 gas and CO2-He mixture up to 50 bar was studied experimentally, delivering collision rates that are in good agreement with the theoretical expectations. The suggested measurement protocol may be used in other high-density media, and potentially in liquids.

Domaines: Optique [physics.optics]; Physique Atomique [physics.atom-ph]; Agrégats Moléculaires et Atomiques [physics.atm-clus]

H. Zhang, B. Lavorel, F. Billard, J.-M. Hartmann, E. Hertz, et al.. Rotational echoes as a tool for investigating ultrafast collisional dynamics of molecules. Physical Review Letters, 2019, 122 (19), ⟨10.1103/PhysRevLett.122.193401⟩. ⟨hal-02398543⟩