Laser-induced fluorescence and two-photon ionisation spectroscopy of the C(3)1Σ+state of the NaK molecule

Abstract
The C(3)1 Sigma + state of NaK has been studied by two complementary techniques: laser-induced fluorescence, recorded at high resolution by Fourier transform spectrometry; and two-photon resonant ionisation spectroscopy. Constants for the state, which dissociates to Na(3p 2P12/)+K(4s 2S12/), are Te=17787.3 cm-1, omega e=69.66 cm-1 and re=4.445 AA. These values are compared with the results of recent ab initio calculations.