Mean Amplitudes of Vibration, Thermodynamic Functions, and Molecular Polarizabilities of Some Monohaloacetylenes

Abstract

AbstractA brief survey of the vibrational and structural data for the monohalo‐acetylenes and their deuterated compounds except the higher member of the series possessing a linear asymmetrical structure with the point group C∞ν is given. The symmetry coordinates, G matrix elements and analytical expression for the mean‐square amplitudes of vibration have been given. The mean amplitudes of vibration at the room temperature have been calculated by the Cyvin's method. A brief discussion of the results follows. The molar thermodynamic functions have been calculated on the basis of a rigid rotator, harmonic oscillator model for the temperature range 100‐2000° K. Molecular polarizabilities have been calculated from a semi‐empirical delta‐function model by using a variational method and delta‐function electronic wave functions. The model enables one to obtain very simple expressions for the parallel and perpendicular components and mean molecular polarizabilities. A comparison of the observed and computed molecular polarizabilities shows that a deviation of nearly 10% is quite reasonable.