The spectrum of singly ionized tungsten, WII

The low configurations in the second spectrum of tungsten have been analyze d by using Penning discharge spectrograms obtained with the Fourier transfo rm spectrograph at the Physics Department, Lund University. Almost 2500 ide ntified lines in the wavelength region 1850 Angstrom to 5 800 Angstrom have yielded 76 even parity and 187 odd parity levels with an estimated uncerta inty of smaller than 0.005 cm(-1). From the observed energy levels Ritz wav elengths are predicted. The observed configurations were theoretically inte rpreted by means of Hartree-Fock calculations and least-squares fit of the parameters to the observed levels. The even 5d(5), 5d(4)6s and 5d(3)6s(2) a nd the odd 5d(4)6p, 5d(3)6s 6p and 5d(2)6s(2)6p configurations were include d in the calculations. From comparisons with observed lifetimes, scaled the oretical transition probabilities have been calculated and are presented.