The high energy¹Σu⁺states of N₂

The results of new high resolution studies of the 1 Sigma u + states of N 2 , both Rydberg and non-Rydberg, are summarized and a table of rotational constants and other data is presented. The b' 1 Sigma u + state has been studied from v=1 to v=28. The irregularities in the lower vibrational levels and their interpretation as being due to a homogeneous interaction with the first 1 Sigma u + Rydberg state c' 4 (i.e. n=4 of (3 sigma g )np sigma u ) are further documented. At higher levels an even stronger interaction, in this case with the next 1 Sigma u + Rydberg state c 5 ' (n=5) is shown to be occurring.