HIGH RESOLUTION MOLECULAR-BEAM LASER SPECTROSCOPY OF STRONTIUM MONOFLUORIDE $(SrF)^{\ast}$

$^{\ast}$ This research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, under contract W-31-109-ENG-38. (1) W.J. Childs, Z. Phys. D 7, 107-112 (1987) (2) W.J. Childs, L.S. Goodman, and I. Renhorn, J. Mol. Spectrosc. 87, 522-533 (1981)Author Institution: Physics Division, Argonne National LaboratoryThe laser induced fluorescence spectrum of the red $A^{2}\Pi - X^{2}\Sigma$ system of SrF has been recorded. Typical line widths of 20MHz are obtained with the laser beam crossing the molecular beam orthogonally. Each rotational line of the $^{88}SrF$ main isotope and $^{86}SrF$ lesser isotope is split into two components by the magnetic hyperfine interaction between the unpaired electron and the $^{19}F$ nuclear spin of 1/2. The rotational line assignment of this band was confirmed by the rf labelling method (1), using previously measured ground state splittings (2). In addition, with our excellent S/N ratio, it was possible to record many lines from the much less abundant isotope $^{87}SrF$, clearly showing hyperfine structure due to the $^{87}Sr$ nuclear spin of 9/2 as well as the hfs due to the $^{19}F$ with its spin of 1/2. Efforts to measure the ground state hyperfine splitting of $^{87}SrF$ by the rf-laser double resonance method are currently underway