Mikhail Kozlov (PNPI) , Sergey Levshakov


Using microwave molecular spectra to search for the possible variation of fundamental constants in astrophysics.


Until recently most astrophysical data on possible variation of the fine structure constant alpha and the mass ratio mu=m_e/m_p were obtained from optical spectra of atomic ions and molecules. However, the microwave spectra are typically much more sensitive to the variation of constants. At present the most stringent limit on mu-variation on the cosmological time-scale (about 10 Gyr) follows from the comparison of the inversion transition in ammonia (lambda=1.2 cm) with rotational transitions of the molecule HC3N: |dmu/mu| < 1.4*10^{-6}. Moreover, the similar technique applied to the molecular clouds in the Milky Way gives tentative evidence for the non-zero variation of mu on the level dmu/mu~10^{-8}. New observations are planned to verify these results. In addition to the inversion line in NH3, one can use microwave transitions in deuterated ammonia NH2D and Lambda-doublet transitions in molecules CH and OH. This will allow to control possible systematics and increase the sensitivity.