(a) Broadband CP-FTMW spectrum of glycolamide from 9.2 to 17.1 GHz. We depict strong a- and b-type R-branch transitions of syn-glycolamide (in blue) as well as some transitions of anti-glycolamide (in red). (b) Zoom-in section of the broadband spectrum showing the rotational transition 2₀₂ ← 1₀₁ of both syn-glycolamide and anti-glycolamide. (c) Same rotational transition measured in the MB-FTMW experiment, displaying the high resolution of our spectrometer. The resonance frequency is determined by the arithmetic mean of two Doppler components. The MB-FTMW spectrum was obtained by averaging 200experimental cycles (four free induction decay signals per cycle).