New Far-Infrared Laser Emissions From Optically Pumped ${\rm CH}_{2}{\rm DOH}$, ${\rm CHD}_{2}{\rm OH}$ , and ${\rm CH}_{3}{^{18}}{\rm OH}$

An optically pumped molecular laser system utilizing a transverse or zig-zag pumping geometry of the far-infrared (FIR) laser medium has enabled the reinvestigation of the CH
₂
DOH, CHD
₂
OH, and CH
₃
¹⁸
OH isotopic forms of methanol for wavelengths > 100 μm. With this system, 28 FIR laser emissions have been discovered with wavelengths ranging from 117.2 to 744.7 μm. Along with the wavelength, each laser emission is reported with its optimal operating pressure, polarization with respect to the CO
₂
pump laser, and relative intensity. Three of the laser emissions generated by CH
³
₁₈
OH support the spectroscopic assignments of FIR laser transitions originally proposed through combination-difference loops. A fourth CH
₃
¹⁸
OH laser emission should contribute to another, incomplete FIR laser scheme.