Improved deuterium bromide 1-0 band molecular constants from heterodyne frequency measurements

Heterodyne frequency measurements have been made on selected deuterium bromide 1-0 band transitions ranging from P(20) to R(17). Difference frequency beat notes between a tunablediode laser whose frequency was locked to the DBr absorption lines and a CO laser whose frequency was either locked or adjusted to a reference synthesized from CO₂ laser frequency standards were measured. The beat note frequency was then combined with the measured CO laser frequency to give the DBr frequency. For two of the measurements, frequency-doubled CO₂ laser radiation was substituted for the CO laser radiation. The measurements included electric quadrupole split triplets comprising the R(0) and P(1) transitions in the D⁷⁹Br isotope. New DBr constants have been determined, and a table of frequencies is presented for the calibration of spectrometers and tunable lasers in the wavenumber range 1600 to 1990 cm^?1. A table of far-infrared frequencies is also given for DBr covering the range from 50 to 206 cm^?1.