ABSORPTION SPECTRUM OF $He_{2}$ MOLECULES IN THE $600-611{\AA}$ RANGE

Author Institution: AFCRL (CRAS) L. G. Hanscom Field, BedfordSix absorption bands of $He_{2}$ have been observed in the $600-611{\AA}$ range. Individual bands exhibit diffuse rotational structure when the absorption cell is cooled with liquid nitrogen. They form a $v^{\prime}$-progression. Attribution is to the transition $\Lambda^{1}\Sigma^{+}_{u} \leftarrow X^{1}\Sigma^{+}_{g}$ of $He_{2}$. Rotational constants, $B_{v***}$ for the upper state are calculated. The dissociation energy and the term value of the upper state are estimated. A minimum height for the potential ``hump'' in the A-state is determined to be 0.059eV. There is a very close connection between emission and absorption bands of $He_{2}$ around $600{\AA}$ and also to well known He-continuum with intensity peak near $800{\AA}$