High-energy-resolution molecular beams for cold collision studies

TL;DR

This paper introduces an alternative Stark deceleration method that aggressively slows molecules to produce molecular beams with narrower energy spreads, enhancing the resolution of cold collision experiments.

Contribution

The paper presents a new Stark deceleration technique that reduces energy spread and makes velocity spread nearly independent of final velocity, improving collision measurement resolution.

Findings

Narrower energy spread in molecular beams achieved.

Velocity spread nearly independent of final velocity.

Enhanced energy resolution for collision studies.

Abstract

Stark deceleration allows for precise control over the velocity of a pulsed molecular beam and, by the nature of its limited phase-space acceptance, reduces the energy width of the decelerated packet. We describe an alternate method of operating a Stark decelerator that further reduces the energy spread over the standard method of operation. In this alternate mode of operation, we aggressively decelerate the molecular packet using a high phase angle. This technique brings the molecular packet to the desired velocity before it reaches the end of the decelerator; the remaining stages are then used to longitudinally and transversely guide the packet to the detection/interaction region. The result of the initial aggressive slowing is a reduction in the phase-space acceptance of the decelerator and thus a narrowing of the velocity spread of the molecular packet. In addition to the narrower energy spread, this method also results in a velocity spread that is nearly independent of the final velocity. Using the alternate deceleration technique, the energy resolution of molecular collision measurements can be improved considerably.