VACUUM U.V. SPECTRA OF HF AND $F_{2}$

Author Institution: Department of Chemistry, Rice UniversityThe absorption spectra of fluorinc an hydrogen fluoride have been observed in the vacuum ultraviolet at wavelengths shorter than 1500 {\AA}. at a dispersion of 3.75 {\AA/}mm. For HF two band systems have been observed and are believed to arise from transitions A $^{1}\Pi\leftarrow X^{1}\Sigma^{+}$ and $B^{1}\Sigma^{+}\leftarrow X^{1}\Sigma^{+}$ in neutral HF. A Birge-Sponer extrapolation for the progression of state A leads to a dissociation energy of $134.6 \pm, 1$ keals/mole for the ground state of HF in good agreement with previous $results.^{1}$ For $F_{2}$, previous $spectra^{2,3}$ have been re-interpreted and extended. Rydberg series converging to the first ionization potential of $F_{2}$ have been established and extended. Further Rydberg series are discussed. Some evidence suggests that the ground state electronic configuration for $F_{2}$ is best written as KK(1\sigma_{g})^{2}(1\sigma_{\mu})^{2}(2\sigma_{g})^{2}(2\sigma_{\mu})^{2}(1\pi_{\mu})^{4}(3\sigma_{g})^{2}(1\pi_{g})^{4}{^{1}\Sigma}_{g}{^{+}} The previously indentified progression of bands a \@ 877 {\AA} is re-interpreted yielding a dissociation energy for fluorine at 38.4 $\pm$ 1.6 keals/mole. $^{1}$J. W. C. Johns and R. F. Barrow, Proc. Roy. Soc., 251, 504 (1959). $^{2}$R. P. Izckowski and J. L. Margrave, J. Chem. Phys., 30, 403 (1959). $^{3}$W. Stricker and L. Krauss, Z. Naturforsch 23a, 486 (1968)