Dynamics and Hydrodynamics of Molecular Superrotors. Issue 22 (18th August 2016)

• Record Type: Journal Article
• Authors: Steinitz, Uri; Khodorkovsky, Yuri; Hartmann, Jean‐Michel; Averbukh, Ilya Sh.
• Is Part Of: Chemphyschem. Volume 17:Issue 22(2016)
• Page Start: 3795
• Page End: 3810
• Publication Date: 2016-08-18
• Subjects: computational chemistry -- laser chemistry -- molecular dynamics -- superrotors; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201600508
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: In recent years, several femtosecond laser techniques have been developed that can make gas molecules rotate extremely fast, whereas the gas stays translationally cold. Herein we use molecular‐dynamics simulations to investigate the collisional dynamics of gases of such molecules ("superrotors"). We found that the common route of superrotors to equilibrium is rather generic. It starts with a long‐lasting "gyroscopic stage", during which the molecules keep their fast rotation and the orientation of their angular momentum despite the many collisions they undergo. The inhibited rotational relaxation is characterized by a persistent anisotropy in the molecular angular distribution, manifested in long‐lasting optical birefringence and in anisotropic diffusion of the gas. Later, the gyroscopic stage is abruptly terminated by a self‐accelerating explosive rotational–translational energy exchange that generates sound and macroscopic vortices with a hot rotating core. Abstract : Spinning in place : Molecular‐dynamics simulations are used to explore the behavior of gas molecules that have been excited to high rotational states (superrotors) but with little initial change in translational motion. The initial "gyroscopic phase", in which the molecules retain their rotation axis and speed during collisions, ends with an explosive rotational–translational energy exchange that generates sound and macroscopic vortices with a hot rotating core.