collisions*

Measurements of collisionally-induced fluorescence can reveal features of the collision dynamics not probed in standard scattering experiments, and hence provide some of the most sensitive tests of quantum-mechanical scattering theories. It is now commonplace to see outstanding agreement between measured and calculated Stokes parameters for scattering on atomic targets. However, in the case of molecular targets, both measurements and calculations of Stokes parameters are rare, and there have been no previous studies showing agreement between theory and experiment.

We have applied the ab initio molecular convergent close-coupling (MCCC) method to study rotationally-resolved electron scattering on molecular hydrogen, allowing calculations of the polarization of emitted radiation following electronic excitation. We have calculated the linear polarization fraction for the Q(1), R(1), and Q(3) branches of the Fulcher-α band, the strongest in the H₂ emission spectrum. We find good agreement with available measurements for all transitions.