Accurate broadband rotational BWO-based spectroscopy

Abstract

The capability, accuracy and precision of broadband spectrometers developed in the Microwave Spectroscopy Lab in Nizhniy Novgorod on a basis of backward wave oscillators (BWOs) are presented. Examples of high accuracy laboratory measurements of molecular transition frequencies, shifts, and line shapes spanning many orders of magnitude in pressure are given. The importance of sensitive broadband line measurements in the millimeter and submillimeter wavelength range to both atmospheric and astronomical observations is discussed in the context of the laboratory precision and accuracy required for their interpretation. The demands on the quality of laboratory measurements have become very stringent. The present state of broadband BWO-based spectroscopy is shown to satisfy these demands. Accurate measurements are also needed for further studies of the physics of the molecules and their interactions. The capabilities and prospects for further research and development are discussed.