15min:

GERMAN YU. GOLUBIATNIKOV, SERGEY P. BELOV AND ALEXANDER V. LAPINOV, Institute of Applied Physics of RAS, 46 Ulyanov str., 603950 Nizhny Novgorod, Russia.

The methanol torsion-rotation spectrum in the first three torsional states has been measured and analysed for a search of m_e/m_p variations from comparison of radio astronomical and laboratory frequencies and for studies of systematic velocity motions in star-forming regions. The investigation is based on Lamb-dip measurements with sub-Doppler spectrometer developed at IAP RAS. CH₃OH-A and -E frequencies have been obtained with an accuracy of 1 kHz at 48-510~GHz for more than 500 transitions in v_t=0, more than 200 transitions in v_t=1 and 100 transitions in v_t=2. For many b-type transitions the removed degeneracy of the CH₃OH levels due to different nuclear spin statistics was measured in a form of doublets with unresolved hf structure. Some a-type transitions show resolved spin-rotational splitting.