Field-Free Molecular Alignment and Orientation

Control of molecular orientation and alignment has been a longstanding goal in chemical reaction dynamics because the outcome of chemical reactions inherently depends on the relative orientation of the colliding species. The earliest methods for obtaining molecular alignment and orientation relied on static electric fields strong enough to overcome the molecule's rotational energy, but these types of techniques are limited by the relatively low field strengths achievable with static electric fields and the fields "dressing" the molecular states causing a change in their chemistry. The advent of high power, ultrafast laser pulses has allowed for new techniques that obtain strong alignment and orientation while bypassing the dressed state problem by having the electric fields present only transiently.