High-resolution spectroscopy of the A(r)(4 Pi)-> X-4 Sigma(-) band system of MoN

The emission spectrum of MoN between 13 200 and 18 400 cm(-1) has been reco rded by means of a microwave discharge and a Fourier Transform spectrophoto meter (FTS). The transition A(4)Pi (r) --> X(4)Sigma (-) has been rotationa lly analysed. Spin-orbit coupling constants have been determined for the A( 4)Pi (r) state. A number of states were studied by the multiconfiguration s elf consistent field (MCSCF) method with linear response (LR) technique and with account of spin-orbit coupling (SOC) as a perturbation. Besides that the multireference configuration interaction (MRCI) + SOC matrix has been d iagonalized. Deviation from an equidistant splitting of the A(4)Pi (r) stat e and the large spin-sublevel splitting of the ground state have been quali tatively explained as due to second-order SOC.