Interfacing a Multipass Cell with a Commercial FTIR Spectrometer: Study of Deuterium Oxide A-Type Bands at 1.5 Microns

The transfer optics system required to couple a four meter multipass cell to a commercial high resolution Fourier transform spectrometer has been designed. A usable optical path length of approximately 300 meters was easily attained with this system. Low pressure, long path measurements were made in the (0,3,1) and (1,1,1) bands of D_2 O in the 1.5 μm region. Line positions and line assignments have been given for both bands, and molecular constants have been determined for the (0,3,1) band.