Knowledge Bank

There has been considerable interest recently in the electronic spectra of diatomic molecules containing transition metal atoms. However, information available on the spectra of monofluoridea of some transition metals such as nickel is scanty. The rotational structure of three bands has been recorded by Pinchemel et al (1979, 81) while Bai & Hilborn (1986) have studied the LIF and Chemilumineacence spectra of these bands. The conclusion of these workers about ground state was not the same. Recently Gopal at al (1998) photograph thermal emission spectra with 45 new bands in the region $\lambda \lambda 4500-4850$ \AA and determined ground state constants. In the present investigation thermal emission spectrum of the NiF has been recorded in the region $\lambda \lambda 4200-4550$ \AA using Saha’s high temperature graphite furnace at a temperature about $2500\circ C$. The spectrum has been photographed on C.Z. Ebert Plane Grating Spectograph at a reciprocal linear dispersion of 7.0 \AA/mm and 3.5\AA/mm. About 85 new bands have been recorded and classified into fifteen short sub systems. The vibrational constants have been determined.