Knowledge Bank

The infrared spectrum of the $2649cm-1$ combination bending mode of hydrogen peroxide has been recorded with resolution of about $0.05cm-1$. This considerably higher than the $0.2cm-1$ resolution obtained for the same band system by Redington, Olson and $cross1$. Our higher resolution reveals that the spectrum is actually that two hybrid bands (A + B type). The center of the $\tau \prime \prime =1,2\to \tau \prime =1,2$ band is at $2649.018cm-1$ and the center of the $\tau \prime \prime =3,4\to \tau \prime =3,4$ band is at $2649.271cm-1$. Most of the assigned lines of Redington, Olson and Cross, while correctly identified, were unresolved doublets, and the ground state constants obtained by these workers represent a non-liner average of constants over the $\tau \prime \prime =1,2$ and $\tau \prime \prime =3,4$ grund torsional states. Both component bands of the weak overtone $2\nu 2$ have also been identified, and a tentative identification of one component of $2\nu 6$ has also been made. Combination differences form the present work will be combined with recent extensive microwave $measurements2$ to give improved molecular constants, particularly $DK$ and the $\tau \prime \prime =1,2$ to $\tau \prime \prime =3,4$ torsional splitting.