Identification of the high-lying Pi component of NiF by laser-induced fluorescence

The laser-induced fluorescence excitation spectrum of jet-cooled NIF has be en studied in the range 435-570 nm. Eight electronic transitions, involving four high-lying Pi components and two lower states, the ground state X(2)P i (3/2), and the low-lying state [0.25](2)Sigma. respectively, have been re corded. Two new Pi components are identified for the first time and their r otational constants are determined. The [20.4]Pi (3/2) component is assigne d as the nu ' = 1 level of the previously known [19.7](2)Pi (3/2) state. Th e [20.3]Pi (3/2) component may be linked to the component of an unreported quarter state. The previously reported [20.0](2)Pi (1/2) component is reass igned as a subcomponent of (2)Delta. (C) 2001 Academic Press.