Abstract

CH₂DF gas was synthesized in high isotopic purity and tested for far-IR laser emission with pumping by a CO₂ laser. Five lines were found, ranging from 169.5 to 498.4 μm. Infrared absorption spectra at 0.005-cm⁻¹ resolution and analysis of the rotational structure permit clear-cut assignment of two lines: 190.3 μm pumped by 10R46 is due to (J, Ka, Kc) of 34 1 33 → 33 1 32 in v₅; 494.8 μm pumped by 10P4 is due to 132 12 → 122 11 in v₆. Molecular constants are reported for these two bands, centered at 1055.544 and 938.301 cm⁻¹, respectively. The spectra show indications of v₉ centered somewhere near 1130 cm⁻¹; unfortunately we have not yet obtained an assignment of lines due to its great weakness and overlapping by the very strong 1055 band. There are problems in finding infrared absorptions sufficiently close to the pumping lines for the other laser lines; it is possible that they may originate in molecules that are vibrationally excited before absorbing the CO₂ laser radiation. Spectra of combination bands lead to parameters that are shown to support this suggestion.

© 1986 Optical Society of America