High-Resolution Laser Spectroscopy of YbCl: The A2Π–X2Σ+ Transition

Laser spectroscopy of the B[17.7]8–X8 and C[19.3]9–X8 transitions of holmium monochloride

“…Finally the observed vibrational spacing of the X state further confirmed the assignment of this state to the f 10 s 2 configuration. The x e of $337 cm À1 for the ground state is significantly higher than the 290 cm À1 found for the 4f 14 6s configuration of YbCl [8], however is consistent with expectations for 4f 10 6s 2 . Thus, vibrational frequencies in the q Supplementary data for this article are available on ScienceDirect (www.sciencedirect.com) and as part of the Ohio State University Molecular Spectroscopy Archives (http://msa.lib.ohio-state.edu/ jmsa_hp.htm).…”

“…It thus seems feasible that this state is therefore the X ¼ 8 state of the f 11 s configuration. If this is the case, the vibrational frequency should be $290 cm À1 as observed for the ground f 14 s configuration of YbCl [8]. Unfortunately, no fluorescence to other vibrational levels was observed from the C state and, if this configurational assignment is correct, then the 350 cm À1 spacing between the two weak transitions observed in dispersed fluorescence from the A state cannot be a vibrational spacing unless there is a very severe perturbation shifting the levels.…”

“…The only chloride previously observed has been YbCl for which the ground 2 R þ state arises from the unpaired s electron on the 4f 14 6s configuration and for which B $ 0:095 cm À1 [8]. For HoCl, the vibrational frequency and X value have shown that the ground X8 state arises from the f 10 s 2 configuration and it has a larger B value of $0.100 cm À1 .…”

“…The missing head can be attributed to the large value of X and the large difference in B values between the C and X states. Using the B values in Table 2, it can be shown that the head should form near the R(6) line but, as the first R line in the C9-X8 transition is R (8), no head will form.…”

High-Resolution Laser Spectroscopy of YbCl: The B2Σ+–X2Σ+ Transition

“…The spin-rotation splitting in the ground state has been discussed in detail in the previous study of the A 2 -X 2 + transition (1). As N increased, this splitting was also resolved in the present B-X spectra and the spin-rotation doubling of the rotational lines in the "blended" branches was used to definitively assign the two heads to the correct spin-rotation component, F 1 and F 2 , in the upper state.…”