INFRARED-EMISSION SPECTROSCOPY AT 100-MU-M - VIBRATION-ROTATION SPECTRUM OF CSI

The vibration-rotation emission spectrum of CsI was recorded in the 11 0-130 cm(-1) region of the spectrum. Although individual rotational li nes were not resolved, we measured the positions of 29 band heads invo lving the vibrational bands from 1-0 to 30-29. These vibrational data when combined with previously measured microwave and millimeter-wave p ure rotational transitions yielded improved Dunham constants. In addit ion, an experimentally derived Born-Oppenheimer potential is also repo rted and compared with the purely ionic internuclear potential of the Rittner model. The results reported here demonstrate that far-infrared emission spectroscopy is a very sensitive technique for detecting hig h-temperature molecules, even at wavelengths around 100 mu m.