Pressure broadening studies on vibration-rotation bands II. The effective collision diameters

Abstract

Using the methods described in part I, the line widths in the fundamental vibration rotation bands of deuterium chloride and carbon monoxide have been measured, under conditions of self-broadening and also in the presence of added gases. The optical collision diameters have been calculated an d com pared with the molecular diameters derived from viscosity data. An attempt has been made to interpret the high effective collision diameters found in term s of intermolecular interactions of different types, and it is concluded that London dispersion forces, resonant dipole effects and quadrupole interactions may be important. The variatin of line width in aband as a function of J quantum number has been measured and considered in terms of these interactions. The results suggest th t further studies of this kind may throw further light not only upon the nature of intermolecular forces but also upon the factors affecting energy transfer in collision.