HF C1F: AN ANTI-HYDROGEN BONDED COMPLEX

Abstract

The structure of the weakly bound complex HF C1F has been determined by molecular beam electric resonance spectroscopy. The spectroscopic constants for the major isotopic species $HF^{35}C1F$ are: $\bar {B} = 2545.404(3) MHz$ $D_{J} = 7.27(30) kHz$ $\mu_{a} = 2.313(1) D$ $eqQ^{C1}_{a} = - 144.746(25) MHz$. The observed structure is not the hydrogen bonded form; rather a near linear F--Cl-F bond is formed with the proton external at nearly the tetrahedral angle. This structure is analogous to that of $(HF)_{2}$ with the relatively positive Cl playing the role of the hydrogen bonding proton. The structure will be discussed in light of elementary concepts of electron donor-acceptor complexes. Present address of Stewart E, Novick: Joint Institute for Laboratory Astrophysics, University of Colorado, Boulder, Colorado, 80309.