Partially deuterated water dimer: are there perspectives for its spectroscopic detection in the atmosphere?

Recent observations of the water dimer third stretching overtone in the open atmosphere lead onto the idea to look for the signatures of partially deuterated dimers in the range of their stretching fundamentals. On the one hand, the third overtone intensity is roughly three orders of magnitude less than that in the fundamental. On the other hand, the natural abundances of the water isotopomers are known to extend below 0.2% with respect to that of the principal one. The gain can be achieved, however, because of the use of the spectral range which is less crowded by the principal water isotopologue rovibrational lines, because of significant isotopic shift of the band origin. This work is targeted at preliminary search of the suitable spectral window and other conditions which might favor the observation of partially deuterated water dimers using FTIR or tunable lasers instruments.