title: State-Specific Collision Dynamics of Molecular Super Rotors with Oriented Angular Momentum.
abstract: An optical centrifuge pulse drives carbon dioxide molecules into ultrahigh rotational states with rotational frequencies of ω ≈ 32 THz based on the centrifuge frequency at the full width at half-maximum of the spectral chirp. High-resolution transient IR absorption spectroscopy is used to measure the time-evolution of translational and rotational energy for a number of states in the range of J = 0-100 at a sample pressure of 5-10 Torr. Transient Doppler profiles show that the products of super rotor collisions contain substantial amounts of translational energy, with J-dependent energies correlating to a range of ΔJ propensities. The transient population in J = 100 is short-lived, indicating rapid relaxation of high J states; populations in J = 36, 54, and 76 increase overall as the super rotor energy is redistributed. Transient line profiles for J = 0 and 36 are consistently narrower than the initial ambient sample temperature, showing that collision cross sections for super rotors increase with decreasing collision energy. Quantum scattering calculations on Ar-CO2(j) collisions are used to interpret the qualitative features of the experimental results. The results of this study provide the groundwork for developing a more complete understanding of super rotor dynamics.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Murray
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Hannah M
authors.initials: HM
authors.lastname: Ogden
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Carlos
authors.initials: C
authors.lastname: Toro
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Qingnan
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: David A
authors.initials: DA
authors.lastname: Burns
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Millard H
authors.initials: MH
authors.lastname: Alexander
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Mullin