Knowledge Bank

An FTIR isotopic study of vacuum UV photolyzed diacetylene (C4H2), 1,3-butadiene (C4H6), and their various deuterated and carbon-13 substituted isotopomers has enabled the assignment of the $\nu 1,C-H$ stretching, and the $\nu 2,C\equiv C$ stretching vibrations, as well as confirmed the previous assignment of a band at $2060.5cm-1$ to $\nu 3$, the second $C\equiv C$ $vibration.1$ Based on the isotopic data, a study of concentration effects, and the results of the calculations by the Wilson GF matrix technique, absorptions at $3307.4cm-1$ and $2083.9cm-1$ are identified as the $\nu 1$ and $\nu 2$ stretching vibrations of $C4H$, respectively