l-Type Doubling in N2O

Doublet separations in nine π—π bands of the linear nonsymmetrical molecule N₂O have been measured in the region 1.5–2.4 μ. In addition to the doublet splitting caused by the ν₂ motion, it is shown that the parallel modes ν₁ and ν₃ contribute measurable amounts to this splitting in π states, so that the doubling constant q_ν is a function of all three vibrational quantum numbers ν_i. The data fit an equation of the form $q_v{\mathrm{=\Sigma }}_i{Q}_i{\mathrm{(v}}_i\text{+1)}$ within experimental error, where i = 1, 2, 3, and the Q_i are called the Coriolis constants. The experimentally determined values are Q₁ = 1.40×10^—4, Q₂ = 3.40×10^—4, and Q₃ = —0.19×10^—4 cm^—1.