Rotationally inelastic scattering of N2 from W(110)

We have measured the translational energy, rotational state population distributions, and angular momentum alignment of monoenergetic, rotationally cold N2 scattered from W(110), as a function of incident energy, incident angle, and exit angle. Translational energy and rotational state distributions indicate that N2 scattering is direct and highly rotationally inelastic. Rotational distributions are well described by Boltzmann fits at all incident energies, incident angles, and exit angles. Rotational distributions do not change with incident angle or exit angle; the distributions scale only with the total incident energy. A comparison between W(110) and Pt(111) shows that the rotational excitation of N2 scattered from W(110) is significantly larger than that N2 scattered from Pt(111). Measurements of angular momentum alignment show that molecules in low J states rotate like helicopters and molecules in high J states rotate like cartwheels for low incident energies (Ei≤0.5 eV). At higher incident energy (Ei=1.0 eV), only cartwheeling rotations are observed.