Spectroscopic investigations of hydrogen bonding interactions in the gas phase. II. The determination of the geometry and potential constants of the hydrogen-bonded heterodimer CH ₃ CN • • • HF from its microwave rotational spectrum

The microwave rotational spectrum of the hydrogen-bonded heterodimer CH$_3$CN $\cdots$ HF has been identified and shown to be characteristic of a symmetric top. A detailed analysis of several rotational transitions for a variety of isotopic species gives the spectroscopic constants summarized in the following table: Rotational constants/MHz, vibration-rotation constants/MHz and vibrational separations/cm$^{-1}$ of CH$_3$CN $\cdots$ HF The following parameters of the molecular potential function of CH$_3$CN $\cdots$ HF have been evaluated using the spectroscopic constants tabulated above: r$_0$(N $\cdots$ F) values and force constants of CH$_3$CN $\cdots$ HF.