We report measurements of the binary and ternary recombination rate coefficients of deuterated isotopologues of H-3(+). A cavity ring-down absorption spectrometer was used to monitor the fractional abundances of H-3(+), H2D+, HD2+ and D-3(+) during the decay of a plasma in He/Ar/H-2/D-2 mixtures.
A dependence of the measured effective recombination rate coefficients on the. helium buffer gas density was observed and hence both the binary and the ternary recombination rate coefficients for H2D+ and HD2+ were obtained in the temperature range. 80-145 K.