Spectroscopy of new CH₃OH FIR laser lines pumped by new CO₂ laser lines

Abstract

The number of CO 2 laser lines available for optical pumping of far-infrared (FIR) lasers has been significantly increased by the development of a new continuous wave (cw) CO 2 laser at the Time and Frequency Division of the National Institute of Standards and Technology in Boulder, Colorado. This system operates on very high-J lines of the normal bands as well as on sequence and new hot-band lines, and has generated numerous new FIR laser transitions in CH 3 OH. These include the new 123 μm world-record holder, pumped by the 9HP(20) hot-band CO 2 line, which is now the most efficient known FIR laser line. Assignments are given for a number of the IR pump – FIR laser energy level and transition systems, based on our high-resolution Fourier transform studies of the FIR and IR spectra of CH 3 OH. Features of the transition system for the 123 μm line and wave numbers for several further potential FIR laser lines are presented.