Microwave optical double resonance of X 1Σ+ of NaK

Abstract

A microwave optical double resonance (MODR) study of the ground state X 1Σ+ is NaK is reported. The ν″ = 0 J = 7→8 and J = 8←9, and ν″4 J = 5←6 rotational transitions were observed as changes in the laser induced photoluminescence intensity with the Ar+ laser coincidences (12–0) band P(8) (4765 Å) and (’–4) band Q(5) (4965 Å), respectively, of the D 1Π–X 1Σ+ system of NaK. The improvement in sensitivity of the MODR technique over traditional microwave spectroscopy is discussed. Improved Dunham coefficients for the X 1Σ+ state are obtained by a weighted merged fit of the previous optical data with the three transitions obtained in the present work.