Knowledge Bank

The $\nu 1$ (N-H stretching) fundamental of $HN3$ between $3l40cm-1$ and $3600cm-1$ has bean recorded at a resolution of $0.004cm-1$ using a Fourier transform spectrometer. This is a type AB hybrid band of a slightly asynmetric top, Where the K-type doubling is resolved up to K = 4. Two acts of $K\prime =1$ sub-bands are observed, indicating an upper state perturbation. In the present work, combination differences between different $K\prime \prime$ levels can be measured directly for $K\prime \prime$ up to 7; they can be combined with previous microwave $measurements1$ to give improved molecular constants for the ground state. The analysis of the weak, badly perturbed $\nu 2+\nu 4$ combination band at $3250Cm-1$ will also be discussed. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$J. Bendtsen and H. Winnewisser, Chem. Phys. Letters 33, 141 (1975).