On the Assignment of Optically Pumped Far-Infrared Laser Emission from CH3OH

New assignments, line intensities, and HITRAN database for CH3OH at 10μm

“…The next difference concerns a subband with origin at 1036.16 cm À1 that is assigned in [16] to both (E,co,2,)2) and (A,co,2,4) transitions throughout most of its range. The latter identification is well founded both from Lamb-dip spectral measurements [20] and from FIR laser assignments [25,29]. However, we have been unable to see any distinct trace of the (E,co,2,)2) subband in the FTIR spectrum.…”

“…We distinguish these upper states with ''/lo'' and ''/hi'' suffixes [25]. While the lower ''/lo'' substates appear more consistent with the position of the m 6 fundamental, we have not yet established the vibrational parentage.…”

“…Previous calculations of torsion-vibration energies for the lower modes of CH 3 OH [25] have shown there are likely to be numerous near-degeneracies within the dense energy level structure. Fig.…”

“…In connection with analysis of FIR laser (14), 9P (24), and 18-10R(16) CO 2 laser lines [25,28], it was discovered that the (E,co,1,)5) subband actually lies about 4.3 cm À1 below the one listed in [16]. The latter subband was reassigned instead to the forbidden OH-bending torsional combination transition, (E,oh,0,)5) (E,gr,1,)5), that borrows intensity through mixing between the m 12 ¼ 0 OH bend and the m 12 ¼ 1 in-plane CH 3 rock [26].…”

Pulsed CH3OH Terahertz Laser Emission Pumped by a TEA CO2 Laser

“…More than 570 lines from 19 to 3030 μm have been observed for the parent l2 CH 3 16 OH species alone and about 2000 Lines in total for all of the isotopomers of methanol [2][3][4][5]. In the past few years, most research has been dedicated on the assignments of the observed THz laser lines from methanol and its isotopomers pumped by CW CO 2 lasers or chopped CO 2 lasers [6][7][8][9][10][11][12]. However, relatively less attention has been concentrated on energy of pulsed optically pumped CH 3 OH THz lasers, and only the relative energy of THz laser has been publicly reported [13,14].…”