The Measurement of Field Gradient Induced Birefringence in Gases

Abstract

This thesis is concerned with the determination of the molecular quadrupole moment and other fundamental molecular properties, of several interesting and important molecular species from measurements of their field gradient birefringence effects. The electric multipole moments and polarizabilities of a molecule are relevant to a wide variety of topics such as intermolecular forces, electrostatic potentials, collision-induced spectroscopy and nonlinear-optical phenomena. Consequently, significantly improved equipment for measuring the field gradient birefringence effect of vapours and gases is described. This apparatus is capable of operating over a temperature range of 293-442 K, at pressures up to 3500 kPa, and incorporates a detection system having a limit of resolution of 2 x 10⁻⁹rad.