Observation and assignment of D218O FIR laser lines optically pumped by a waveguide CO2 laser

By means of the molecular constants of the ground state and of the first excited state of the bending vibration, ν2 = 1, of D218O, the authors have been able to assign most of the FIR far infrared emissions reported in the literature. Moreover, they predicted and observed two FIR laser lines which fall in the range of tunability of our CW waveguide CO2 laser. The stronger line was also frequency measured and found to be νFIR = 2611.4185(10) GHz, thus filling a gap in the presently available comb of frequency-measured FIR laser lines. Also the wavelength precision of the assigned lines was improved by about two orders of magnitude