Knowledge Bank

The reactive $F2$BOH molecule was first detected by microwave $spectroscopya$, and very recently observed by matrix IR $spectroscopyb$. We report here the first high resolution infrared study of $F2BOH$. $F2$BOH has been produced in a slow flow of ($\mathrm{<mrow\; data-mjx-texclass="ORD">11</mrow>}$B and natural) $BF3$ through a glass tube filled of some specks of quartz (all using stainless stell equipment) on which water had been deposited. The IR spectrum has been recorded from $400cm-1$ to $1600cm-1$ at high resolution $(2-3\times 10-3cm-1)$ using the Wuppertal Bruker 120 HR interferometer equipped with a cell of 1.2 m path length. In addition, ground state parameters have been determined from recent microwave measurements performed in $Lillec$. Among the recorded infrared bands, two c-type out-of-plane fundamental bands $v8(BF2$ bend) and $v9$ (OH torsion) located at $684.16cm-1$ and $522.86cm-1$, respectively, were analysed using a simple Watson -type Hamiltonian. The a/b type hybrid $2\nu 9$ and $\nu 4$ bands centered at 1042.87 and $961.49cm-1$ were also studied. The analysis of $\nu 4$ (OH bending mode) was complicated by the existence of ``classical'' vibrational rotational resonances linking the $41$ energy levels with those of the $7191$ dark overtone state. More surprising is the fact that both in the $2\nu 9$ and $\nu 4$ bands, the P- and R-lines exhibit a regular doublets structure (of about 0.005 and $0.003cm-1$ respectively) which indicates the existence of large amplitude motions in the $F2$BOH molecule.