Data available on the 5d(2), 5d6s, and 5d6p configurations in the Yb I isoe
lectronic sequence have been critically reviewed by means of calculations w
ith the orthogonal operators. The study included ions from Ta rv through Hg
XI. Quite good agreement of the calculations with the experimental data fo
r the ions from Ta Iv through Au X has been achieved. A temporarily assigne
d value for the 5d(2) S-1(0) level in the analysis of Re VI has been confir
med, and a previously unknown 5d6p P-3(0) level in Au X has been establishe
d. For Hg XL, at least three of nine published levels in the 5d2 configurat
ion and four of eleven levels in the 5d6p configuration are suspect because
of their abnormal deviations from the calculated positions. The isoelectro
nic evolution of the parameter A,,. that describes the two-particle magneti
c cls interaction in the 5d6s configuration as well as of the two effective
parameters S-1 and S-2 that describe higher-order effects in the 5d6p conf
iguration was studied for the first time to the author's knowledge in the Y
b I sequence. The present calculations based on the orthogonal operators re
sulted in 5-10 times better agreement with the experimental data than did t
he conventional calculations. (C) 2001 Optical Society of America.