Searching for the building block of deuterated ammonia II a continuation

Coordinator: M. Gerin, D. Lis, E. Roueff, G. Guesten

We propose to use APEX for investigating deuterated ammoniaisotopologues NH_2D,ND_2H and ND_3 ,and the gas phase intermediate ofmultiply deuterated ammonia, ND, in the L1689Ndense core. The ground state submillimeter NH_2D, ND_2H and ND_3 lineshave been successfully detected at CSO by our team in this source,showing that the lines are easily detected and the emission might bespatially extended. The spatial distribution of the ND_2H and ND_3emission bears important information on the process of D fractionationas it is extremely sensitive to the local physical and chemicalconditions. Furthermore, ND is predicted to be abundant in thepre-stellar core conditions from a gas-phase model, which considers thedetailed deuterium substitutes of ammonia and simple compounds species.The interest for searching ND has been renewed by the experimentalfinding that NH is an important product in the dissociativerecombination of N2H+ . A similar behaviour is expected for thedissociative recombination of N2D+ leading to ND. ND has an extensivehyperfine structure pattern near 492, a range well suited for APEX.With the 1GHz bandpass, ND and C can be observed with the same Rxtuning, C providing a stable frequency reference.
ND_2H data have been obtained with APEX on L1689N last august. Weask for a continuation on L1544C as L1689N is not visible in October.

Program is available and data products can be downloaded