New FIR laser lines from optically pumped CH3OH: Measurements and assignments

26 new FIR laser lines have been observed in CO
2
laser pumped CH
3
OH, and together with some previously observed lines their wavelengths have been measured with a relative accuracy of
3 \times 10^{-4}
by using the FIR resonator as a scanning Fabry-Perot interferometer. Based on the internal consistency of the data, it is suggested that a number of the lines originate from combination bands involving simultaneous excitation of the CO stretch mode and a different vibrational mode.