Knowledge Bank

Several vibration-rotation absorption bands of allene $(C3H4)$ and $allene-d4(C3D4)$ have been measured with high resolution. From measurements of a parallel and a perpendicular band of $C3H4$ the following constants were obtained: $B0=0.29632\pm 0.00004cm-1,DJ=11.6\pm 1.6\times 10-8cm-1$ and $DJK=4.6\pm 1.2\times 10-5cm-1$. The best measurements on $C3D4$ were for a parallel band at $2790.25cm-1$ for which the values $B0=0.23209\pm 0.00005cm-1$ and $DJ=4.1\pm 1.3\times 10-8cm-1$ were obtained. Several perturbations of the levels of $C3D4$ will be described and discussed.