Abstract
The microwave spectrum of the doubly deuterated cyanomethyl radical (D2CCN) in its ground electronic state ((2) B (1)) has been observed for the lowest four rotational transitions (N(Ka,Kc) = 1(0,1)-0(0,0), 2(0,2)-1(0,1), 2(1,2)-1(0,1) and 2(1,1)-1(1,0)) using a Fourier transform microwave spectrometer in combination with a pulsed discharge nozzle. A total of 394 hyperfine components were measured and subjected to a least squares analysis which allowed determining twelve hyperfine constants for nitrogen and deuterium nuclei. With this new set of molecular constants we obtained accurate predictions for low N rotational transitions with hyperfine structure, and searched for this species in TMC-1.