The absorption of ethylene in the 10-μm region

The ν₇, ν₁₀, and ν₄ interacting band system has been studied from three complementary sources: classical, diode laser, and waveguide laser spectra. In addition to the two first-order Coriolis interaction terms associated with ζ_7.10^a and ζ_4.10^b, we were obliged to introduce the corresponding second-order terms to obtain a statistical agreement between calculated and experimental data. High-quality vibrational and rotational data are presented for the two infrared active fundamentals, ν₇ and ν₁₀, and the rotational constants for the inactive ν₄ fundamental are determined for the first time. We also present the list of all the infrared transitions starting from the vibrational ground state of ethylene and being in quasi coincidence with CO₂ or N₂O laser lines.