High-resolution spectra of a 232ThI4 / 230ThI4 electrodeless discharge lamp were obtained from 5600 to 36000 cm-1 with a Fourier-transform spectrometer. The splittings of more than 2800 Th I isotopic doublets were measured to an accuracy of 0.001 cm-1. Level isotope shifts were determined for 274 even and 318 odd levels of Th I.
© 1983 Optical Society of America
R. Engleman, Jr. and B. A. Palmer, "Precision isotope shifts for the heavy elements. II. Neutral thorium," J. Opt. Soc. Am. 73, 694-701 (1983)