Infrared Laser Spectroscopy of Free Radicals and Ions. II. Analysis of the ν_1 Band of NF_2 (tilde{X}^2B_1)

Almost three hundred absorption lines of the v_1 fundamental band of NF_2(tilde{X}^2 B_1) have been assigned by using high resolution infrared spectroscopy with tunable diode lasers. The spectrum resembles a perpendicular band of a prolate symmetric top with Q-branches which have high K_a quantum numbers presenting the most distinguishable features. A combined fit of nearly one hundred infrared lines and eighteen microwave transitions yields a new set of rotational, distortion and spin-rotation parameters for the v_1 = 1 level. The band centre is 1074.9897(8) cm^-1. A preliminary analysis of the v_1-v_3 Coriolis interaction through the inertial defect is presented.