HYPERFINE SPECTRUM OF KCL AS OBSERVED BY MOLECULAR BEAM ELECTRIC RESONANCE SPECTROSCOPY

Author Institution: St. Olaf CollegeWe have observed weak-field hyperfine transitions in KC1 for vibrational-rotational states (v,J) = (0, 2-9)and (1, 2-4) using a high resolution molecular beam spectrometer. Linewidths of the observed transitions are 200 Hz (FWHM). Analysis of the (v,J) = (0,2) data yields the following set of hyperfine interaction constants for the $^{3 9}K^{3 5}Cl$ isotope (in units of kHz): [FIGURE} \begin{eqnarray*} (eqQ)_{K} &=& - 5664.74 (5)\\ (eqQ)_{Cl} &=& 56.2 (5)\\ ^{c}K &=& 0.035 (10)\\ ^{c}Cl &=& 0.46 (1)\\ d_{T} &=& 0.07 (2)\\ d_{S} &=& 0.01 (2)\\ \end{eqnarray*} The quadrupole constants lie outside the experimental uncertainties of previously-reported measurements made at lower resolution and high field on the J = 1 $state.^{1}$ Analysis of the higher rotational and vibrational states is in progress. $^{1}$1 R. van Wachem and A. Dymanus, J. Chem. Phys. 46, 3749 ( 1967). This work is supported in part by a Northwest Area Foundation Grant of Research Corporation