ABSORPTION SPECTRUM OF $H_{2}$ IN THE REGION BELOW 850{\AA}.

$^{1}$ H. Beutler and H. O. Junger, Zeits fur Physik, 100, 80 (1936); 101, 285 (1936).Author Institution: Air Force Cambridge Research LaboratoriesThe absorption spectrum of $H_{2}$ has been investigated with a 21-ft. normal incidence spectrograph in the second order using the helium continuum as background. Rydberg states, $(np\sigma) ^{1}\Sigma^{+}_{u}$ and $(np \pi) ^{1}II_{u}$ were identified up to $n = 10$. The ionization energies of $H_{2}$ obtained from $Q (1)$ line series of the $(np \pi) ^{1}\Pi_{u} \leftarrow X ^{1}\Sigma^{+}_{g}$ transition were $124417 \pm 3 cm^{-1}$ for $v^{1} = 0$ and $126610 \pm 5 cm^{-1}$ for $v^{1} = 1$. The former value is about $16 cm^{-1}$ less than that obtained by Beutler and $Junger.^{1}$ The observed Rydberg series which converge to higher vibration levels (up to $v^{1} =5$) of the $H^{+}_{2}$ ground state will also be discussed