ISOTOPE SHIFT IN THE ABSORPTION SPECTRUM OF $N_{2}$ IN THE VACUUM ULTRAVIOLET REGION $(800-1000{\AA})$

Abstract

The vibrational isotope shift of the absorption bands of $N_{2}$ has been studied in the region from $800{\AA}$ to $1000{\AA}$. A 3-meter normal incidence vacuum spectrograph was used in combination with the helium continuum as background. According to our analysis, the vibration quantum numbers assigned to the lowest observed vibration bands for several electronic $states^{\ast}$ are as follows: [FIGURE] $^{\ast}$ R. E. Worley. Phys. Rev. 61, 207 (1943) 65, 249 (1944).