RADIO PHYSICS AND RADIO ASTRONOMY

Results of improvement of the automated millimeter-wave spectrometer
of the Institute of Radio Astronomy NAS–Ukraine aimed at reaching a sub-Doppler resolution on the basis of the Lamb-dip observation are presented. Some hardware solutions of the improvement and some results of investigation of the methanol CH₃OH molecule rotational spectrum are discussed. Measured value of the Lamb-dip width of 10 kHz for J=1←0 transition of CO molecule agrees well with the broadening caused by collisions with cell walls. This value corresponds to improvement of spectral resolution by an order of magnitude. Results of investigation of the methanol spectrum confirm the anomalous hyperfine structure for a number of transitions.

Key words: radiospectrometer, sub-Doppler spectral resolution, Lamb dip, direct digital synthesizer

Manuscript submitted 06.11.2014

Radio phys. radio astron. 2014, 19(4): 364-374 

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