High-Temperature Infrared Emission Spectra of DCN and DCN

The infrared spectra of two isotopomers of deuterium cyanide, D¹²C¹⁴N and D¹³C¹⁴N, were measured in emission at temperatures of 1370 K and 1520 K, respectively, in the range from 450 to 850 cm⁻¹ and, for D¹²C¹⁴N, also from 1800 to 2800 cm⁻¹. Assignments were made for rovibrational transitions to high bending states, v₂=9 for D¹³C¹⁴N and v₂=11 for D¹²C¹⁴N. To aid and verify the assignments, bands of the lower bending states, up to v₂=3, were also measured in absorption at room temperature. A global fit was made of all measurements available to us for each isotopomer. In addition to giving the rovibrational constants for each state measured, the power series expansion constants are also given and compared with those of the other deuterium cyanide isotopomers. The D¹²C¹⁴N laser transitions are verified as arising from the consequences of the Coriolis interaction between the J=21 levels of the 02⁰2 and 09^1e0 states.