This work reports the discovery of 45 new optically pumped far-infrared (FI
R) laser lines from CH3OD in the range 42.6 mu m to 207.2 mu m. A highly ef
ficient CO2 laser was used as the pump laser for an Optically-pumped Fabry-
Perot FIR laser. The frequencies of most of the new lines were measured in
the range 1.7 to 6.4 THz. Twenty-eight CO2 lines were used as pump lines; n
ineteen of these had frequencies lower than those previously used to pump C
H3OD in a FIR laser. Sixteen of the new FIR lines had absorption transition
s which belong to the OD bending vibrational mode.