A newly designed molecular beam Fourier transform microwave spectrometer in the range 1–4 GHz

Abstract

We report on a new design for a Fourier transformmicrowave spectrometer in the spectral region 1–4 GHz, specially constructed for the investigation of rotational spectra of heavy van der Waals complexes. In contrast to the commonly known molecular beamspectrometers using a Fabry–Perot resonator working with TEM00q modes, the proposed design employs a different type of resonator operating with TE01q modes. This resonator allows for compact dimensions even at cut‐off wavelengths above 0.1 m. Details of the design, performance data, and example spectra of stable molecules and complexes are given.