The emission band system c² Σ ⁺ — x² Π of NH⁺

Abstract

Five red degraded bands belonging to theC ² Σ ⁺ —X ² Π system of NH⁺ were excited in a mild condensed discharge through flowing ammonia and were photographed on a 3.4 meter Ebert grating spectrograph at a dispersion of 2.5 A/mm. The rotational analyses of these bands enabled us to evaluate the vibrational and rotational constants accurately. The rotational energy levels of theΠ ⁺ andΠ ⁻ levels of theν=0 and 1 levels of the ground state,X ² Π, were fitted in James expression using two sets of rotational constants. The perturbations observed in theX ² Π state caused by thea ⁴ Σ ⁻ state were examined in greater detail.