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Simulating Spatial Microwave Manipulation of Polyatomic Asymmetric‐Top Molecules Using a Multi‐Level Approach
Author(s) -
Graneek Jack B.,
Merz Simon,
Patterson David,
Betz Thomas,
Schnell Melanie
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600538
Subject(s) - polyatomic ion , microwave , molecular beam , rotational spectroscopy , chemistry , molecule , crossed molecular beam , stark effect , supersonic speed , range (aeronautics) , molecular dynamics , computational physics , atomic physics , computational chemistry , physics , materials science , quantum mechanics , mechanics , spectral line , composite material , organic chemistry
A numerical approach that employs a multi‐level dressed state method to determine the AC‐Stark shifts of molecular rotational energy levels is described. This approach goes beyond the two‐level approximation often employed for simpler molecules, such as ammonia and acetonitrile, and is applicable to a variety of molecules. The calculations are used to develop experiments aimed at focusing, guiding, decelerating and trapping neutral, polyatomic, asymmetric‐top molecules by using microwave fields. Herein, numerical calculations are performed for acetonitrile and 4‐aminobenzonitrile. Based on these results, trajectory simulations are performed to predict the outcome of microwave focusing experiments in the TE 1,1, p mode of a cylindrically symmetric microwave resonator. Simulations show that, for such an experimental setup, microwave focusing and guiding of 4‐aminobenzonitrile requires starting longitudinal velocities close to, or below, 100 m s −1 , that is, much lower than values obtained with standard molecular beam techniques, such as supersonic expansion. Therefore, alternative beam‐generation techniques, for example, buffer‐gas‐cooled molecular beams, are required to extend microwave manipulation methods to larger and more complex molecules.