Imaging rotational energy transfer: comparative stereodynamics in CO + N and CO + CO inelastic scattering.

State-to-state rotational energy transfer in collisions of ground ro-vibrational state CO molecules with N molecules has been studied using the crossed molecular beam method under kinematically equivalent conditions used for CO + CO rotationally inelastic scattering described in a previously published report (Sun , , 2020, , 307-309). The collisionally excited CO molecule products are detected by the same (1 + 1' + 1'') VUV (Vacuum Ultra-Violet) resonance enhanced multiphoton ionization scheme coupled with velocity map ion imaging. We present differential cross sections and scattering angle resolved rotational angular momentum alignment moments extracted from experimentally measured CO + N scattering images and compare them with theoretical predictions from quasi-classical trajectories (QCT) on a newly calculated CO-N potential energy surface (PES).

Detection of the O A'Δ Herzberg III state by photofragment imaging.

Photofragment imaging is shown to provide a sensitive method for detection of the O2 A'3Δu Herzberg III state using a one-laser dissociation/O(1D) resonance enhanced multiphoton ionization (REMPI) scheme with a focused nanosecond dye laser beam tuned to 203.8 or 205.2 nm, combined with velocity map imaging of the atomic oxygen photofragment.

Communication: State-to-state inelastic scattering of interstellar O with H.

Molecular oxygen (O) is predicted to be a major reservoir of elemental oxygen in dense interstellar molecular clouds. However, the abundance of O derived from astronomical observations is much lower than expected. Solving the discrepancies between models and observations requires a review of the chemistry and collisional excitation of O in space.

Collision energy dependence of state-to-state differential cross sections for rotationally inelastic scattering of HO by He.

The inelastic scattering of HO by He as a function of collision energy in the range 381 cm to 763 cm at an energy interval of approximately 100 cm has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the HO and He beam. We measured the state-to-state differential cross section (DCS) of scattered HO products for the final rotational states J = 1, 1, 2 and 4.

State-to-State Inelastic Scattering of O2 with Helium.

Molecular oxygen (O2) is extremely important for a wide variety of processes on and outside Earth. Indeed, O2–He collisions are crucial to model O2 abundance in space or to create ultracold O2 molecules. A crossed molecular beam experiment to probe rotational excitation of O2 due to helium collisions at energies of 660 cm–1 is reported.