Production, characterization and control of polarization states of molecules (specifically, alignment and/or orientation) are of importance for investigating in detail the stereodynamics of elementary processes involving elastic, inelastic and reactive events and also to prepare targets for selective photodynamical investigations. The focus here is on those molecular beam techniques which show perspectives in the applications offering appealing features for “duty cycle” and intensity characteristics. After a review of the basic experimental advances, mainly obtained in the last ten years, the attention will be addressed to recent studies carried out on the collisional alignment of hydrocarbon molecules and on orientation of symmetric top molecules by exploiting honeycomb hexapole fields. The first case is a prototype of “natural” polarization techniques, the second one of those where polarization is “forced” by external fields.

Molecular beam experiments on collisions between oxygen molecules were performed at low energy and high angular resolution to permit observation of the “glory” interference effect. A novel technique for aligning the rotational angular momentum of the colliding molecules is exploited. Analysis of total scattering cross section data yields for the ${\mathrm{O}}_2-{\mathrm{O}}_2$ bond an energy of $1.65\pm 0.08\mathrm{kJ}̇{\mathrm{mol}}^{-1\mathrm{}}$ for the most stable configuration (parallel molecules) at a distance of $0.356\pm 0.007\mathrm{nm}$. These results indicate that most of the bonding in the dimer comes from electrostatic (van der Waals) forces but chemical (spin-spin) contributions are not negligible.