title: Dynamics and Hydrodynamics of Molecular Superrotors.
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.
authors.affiliation: AMOS and Department of Chemical Physics, Weizmann Institute of Science, 234 Herzl St., Rehovot, 76100, Israel.
authors.forename: Uri
authors.initials: U
authors.lastname: Steinitz
authors.affiliation: AMOS and Department of Chemical Physics, Weizmann Institute of Science, 234 Herzl St., Rehovot, 76100, Israel.
authors.forename: Yuri
authors.initials: Y
authors.lastname: Khodorkovsky
authors.affiliation: Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS (UMR 7583), Université Paris Est Créteil, Université Paris Diderot, Institut Pierre-Simon Laplace, 94010, Créteil Cedex, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Hartmann
authors.affiliation: AMOS and Department of Chemical Physics, Weizmann Institute of Science, 234 Herzl St., Rehovot, 76100, Israel.
authors.forename: Ilya Sh
authors.initials: IS
authors.lastname: Averbukh
keywords: computational chemistry; laser chemistry; molecular dynamics; superrotors