Sensitivity of microwave spectra of deuterated ammonia to variation of electron-to-proton mass ratio

Abstract

We estimate sensitivity coefficients Q_μto variation of the electron-to-proton mass ratio μfor microwave transitions in partly deuterated ammonia NH2D and ND2H. Because of the mixing between rotational and inversion degrees of freedom the coefficients Q_μstrongly depend on the quantum numbers of the transition. This can be used for astrophysical search for possible variation of the constant μ.

7 pages, submitted to J. Phys. B, Special Issue on High Precision Atomic Physics; v2: corrected misprints in Tab. 2&3