15min:

A. V. LAPINOV, G. YU. GOLUBIATNIKOV, Institute of Applied Physics of RAS, 46 Ulyanov str., 603950 Nizhny Novgorod, Russia; A. P. VELMUZHOV, Institute of Metalloorganic Chemistry of RAS, 49 Tropinin str., 603950 Nizhny Novgorod, Russia; J.-U. GRABOW, Institute of Physical Chemistry and Electrochemistry, Leibniz University of Hannover, Callinstrasse 3A, 30167 Hannover, Germany; AND A. GUARNIERI, Technical Faculty of Christian Albrecht University of Kiel, Kaiserstrasse 2, 24143 Kiel, Germany.

We report results of precise sub-Doppler spectroscopy of HC₃N, H¹³CCCN, HC¹³CCN, HCC¹³CN and HCCC¹⁵N at 45-510~GHz with Lamb-dip spectrometer of IAP RAS. Hf structure of rotational transitions of all above species below 27 GHz as well as inversion transitions of NH₃(1,1) and (2,2) were measured using FTMW spectrometer of University of Hannover. New comparison of HC₃N and NH₃ laboratory frequencies with radio astronomical observations of dark clouds ^, shows an upper limit of m_e/m_p variation in our Galaxy as \le3 10^-9.