Knowledge Bank

Potassium atoms and hydrogen halides deposited in argon and krypton matrices react to yield a radical species whose spectral parameters are closely described in terms of an ionic product, $KH+X-$(X = Cl or Br). Such a structure corresponds to the short lived complex long postulated as an intermediate in the analagous gas phase reactions, M + HX (M = alkali). For $KH+Cl-$ and $KH+Br-$ in argon matrices, the measured spectral parameters are: $aH=432$ Gauss and $aK=19$ Gauss, with $g=2.0112$. By comparison with ``free” hydrogen atoms ($aH=508$ gauss, $g=2,0133$, for an argon matrix) the spin density on the proton in $KH+$ is measured to be $\sim$85%. These results, and some preliminary data from the analagous sodium and rubidium reactions, are discussed in terms of a plausible bonding scheme for complexes MHX.