Knowledge Bank

Infrared spectra of OC-HF, $O13C-HF$, and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}OC-HF$ have been observed in the vicinity of the HF stretching fundamental using a difference frequency laser spectrometer and a long pathlength thermal equilibrium $(T\ast 195K)$ White cell. The results on the OC-HF isotopic form extend previous White cell and molecular beam measurements by Kyro $etal.1$ and Jucks $etal.2$. The $\nu 1$ band origins for the complexes: $3844.0294cm-1$ for OC-HF, $3843.7284cm-1$ for $O13C-HF$, and $3843.8731cm-1$ for $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}OC-HF$, are all red shifted from the fundamental of uncomplexed HF and do not exhibit a systematic trend with CO stretching or bending frequency. The observed positive $\Delta Bvalues(B\prime -B\prime \prime )$ are consistent with the increased van der Waals binding in the $v1=1$ excited state. The homogeneous linewidths for the transitions are large (HWHM * 180 MHz with roughly equal contributions from pressure broadening and vibrational predissociation) and essentially isotope independent. Local perturbations are observed for OC-HF and $\mathrm{<mrow\; data-mjx-texclass="ORD">18</mrow>}OC-HF$, but not for $O13C-HF$.