Design of a ring-shaped traveling-wave Zeeman decelerator for both light and heavy molecules

Taming a broader range of molecular species with large density has been a long-standing goal in molecular science. Heavy molecules with masses greater than 100 amu are of particular interest for precision measurements. However, decelerating a fast-moving beam of such heavy molecules to rest remains challenging for Zeeman deceleration. Moreover, the traditional approach of pulsed Zeeman decelerator suffers from serious molecular loss during deceleration, significantly limiting its potential applications. Herein, we present a proposal of ring-shaped traveling wave Zeeman decelerator (RTWZD) featured with true three-dimensional smoothly moving magnetic potential wells that effectively solve the above intractable problems. With the RTWZD approach, not only can the density of the molecule be greatly increased but also the range of molecular species for Zeeman deceleration can be extended from light to heavy. The performances of the RTWZD are characterized by theoretical analysis and numerical simulations, utilizing a group of atoms and molecules such as Li7, O216, Sr88F19, and Yb174F19 as testers. Notably, losses encountered in the traditional Zeeman decelerator can be avoided, yielding more than two orders of magnitude improvement in molecular density. These characteristics of the RTWZD make it an ideal toolbox to produce cold and dense atomic/molecular samples, with promising prospects for cold collision, sympathetic cooling, and precision measurement.