Infrared intensities and Coriolis interactions in ethylene

Abstract

The infrared band intensities of ethylene and ethylene‐d 4 were measured in the gas phase using the pressure broadening method. From the analyses of Coriolis interactions between ν7 and ν10 and between ν7 and ν12, the relative signs of (∂p/∂Q 7), (∂p/∂Q 1 0), and (∂p/∂Q 12) have been determined. The obtained band intensities were analyzed by the least squares method with the aid of the results from Coriolis analyses and CNDO/2 calculations. The correct sign combination of (∂p/∂Q i ) have successfully been determined. The resulting values of the intensity parameters (∂p/∂S j ) are found consistent with the empirical rule for the sense of the dipole moment derivatives.