Glory and Resonance Effects in the Index of Refraction for Atomic Waves

We have performed the first detailed calculation of the index of refraction of a gas (argon) for an atomic wave (sodium). The index depends rapidly on the wave vector kr describing the relative motion and exhibits two interesting effects: Breit-Wigner-type resonances at very low kr values, and intense glory oscillations over a large range of kr values. A recent experiment has measured this index of refraction, and our calculation using a very accurate sodium-argon potential and taking into account the thermal motion of argon, agrees quite well with the experimental result.