Optically pumped FIR laser lines from CH3OH: New laser lines, frequency measurements, and assignments

We report the identification and characterization of eight new FIR laser li nes from methanol (CH3OH) in the range 48.4 to 453.7 mu m pumped by sequenc e and hot bands of a cw CO2 laser. Frequency measurements for most of the n ew FIR laser lines and from previously reported ones were obtained in the r ange 0.6-6.8 THz with a one-sigma reproducibility of two parts in 10(7). We propose an assignment of energy levels for two of the new laser lines and for five pumped by 10R(46) previously reported. The high frequency lines wi th absorption centers outside of the tuning range of the CO2 laser pump sho wed doublets. These were used to evaluate the offsets of the CO2 absorption transitions.