The Absorption Spectrum of Nitric Oxide in the Vacuum-uv Region; the β and γ Rydberg series of ^<15>NO

Abstract

The absorption spectrum of the isotopic molecule ^<15>NO in the 60-100nm region was examined by means of the high resolution spectroscopy with the reciprocal dispersion 0.6A/mm. The β series was observed up to n=26; the series limit 133 566cm^<-1>, corresponding to the v=0 level of the ionized state b ^3Π. The γ series were found up to n=28; it converges to the v=0 level in A ^1Π state in ^<15>NO, 147810cm^<-1>. The converging limits as well as each Rydberg member in the both series are agreement with those of the regular NO. It, therefore, is doubtless these series are the (0,0) transitions. Without any detailed isotopic study, the previously observed β and γ series have been identified to be the (0,0) transitions. The equilibrium internuclear distances of the converging states are very close to that of the ground state in the neutral one, and consequently, the most intense series must be the transitions with v'=0. The present work, however, is the first to provide direct evidence by means of isotopic study.