THE INTERMOLECULAR POTENTIAL BETWEEN AN ATOM AND A DIATOMIC MOLECULE - THE STRUCTURE OF ArC1F

Abstract

The radio frequency and microwave spectrum of ArC1F has been measured by molecular beam electric resonance spectroscopy. The molecular constants are: [FIGURE] The atomic arrangement is Ar-C1-F, and the vibrationally averaged argon-chlorine distances are, 3.3301(1) {\AA} and 3.3290(1) {\AA} in $Ar^{35}$ClF and $Ar^{37}$CIF, respectively. The Ar-C1F bond stretching frequency is $47 cm^{-1}$. From the values of eqQa it was determined that the equilibrium structure is linear and the angle bending frequency is $40 cm^{-1}$. The linear structure is striking evidence against the validity of an additive pair potential for an atom and a diatomic molecule. The observed structure is well predicted by Walsh’s rule for triatomic molecules.