Controlling rovibrational state populations of polar molecules in inhomogeneous electric fields of the Stark deceleration: molecular dynamics and quantum chemistry simulations

Emil Zak; Jochen Küpper; Andrey Yachmenev

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arXiv · 2506.04798

Controlling rovibrational state populations of polar molecules in inhomogeneous electric fields of the Stark deceleration: molecular dynamics and quantum chemistry simulations

Emil Zak·Jochen Küpper·Andrey Yachmenev

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Abstract

We propose a modified Stark-chirped rapid adiabatic passage technique for a robust rovibrational population transfer in the gas phase molecules in the presence of certain inhomogeneous electric fields. As an example application, the new state switching scheme is shown to greatly enhance the process of slowing polar ammonia molecules in the Stark decelerator. High-level quantum mechanical simulations show that a virtually complete population inversion between a selected pair of weak-field and strong-field seeking states of NH$_3$ can be achieved. Strong dc electric fields within the Stark decelerator are used as part of the rovibrational population transfer protocol. Classical-dynamics simulations for ammonia demonstrate notable improvements in the longitudinal phase space acceptance of the Stark decelerator upgraded with the state switching and an increased deceleration efficiency with respect to the standard Stark deceleration technique.

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Emil Zak, Jochen Küpper, Andrey Yachmenev. 2025-06-05. Controlling rovibrational state populations of polar molecules in inhomogeneous electric fields of the Stark deceleration: molecular dynamics and quantum chemistry simulations. https://arxiv.org/abs/2506.04798

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