LONG-WAVELENGTH TRANSITIONS AND IMPROVED ENERGY-LEVELS OF TRIPLY IONIZED ZIRCONIUM (ZR-IV)

Fourteen new spectral lines of Zr IV lying between 3200 and 4600 Angst rom were observed with a sliding spark discharge and a 10.7-m normal-i ncidence spectrograph. The lines were classified as transitions betwee n highly excited energy levels of this ion. The measured wavelengths p rovide improved values for the known energy levels as well as a value for the previously unknown 6h H-2 term. Wavelengths with standard unce rtainties varying from +/-0.0005 to +/-0.0018 Angstrom were determined from the optimized level values for a group of lines between 445 and 1291 Angstrom. An improved ionization energy was determined as 277 602 .8 +/- 0.5 cm(-1) (34.41837 +/- 0.00006 eV). (C) 1997 Optical Society of America.