The Influence of a Strong Magnetic Field on the Dielectric Constant of a Diamagnetic Fluid

The effect of a strong magnetic field on the static dielectric constant of a diamagnetic fluid is investigated using statistical mechanical methods; a formula is derived relating the dielectric constant to the square of the field strength. The theory indicates that the change in is very small in non-polar substances (although it is detectable in magnetic double refraction experiments), but should be measurable in polar liquids; it is known to be substantial in `liquid crystals', and it is suggested that it might also be large in solutions of large molecules. In a polar substance the chief contributor to the change in is related to the anisotropy in the diamagnetic susceptibility tensor and is proportional to the square of the molecular electric dipole moment. Relationships between the effect and electric and magnetic double refraction are established. Experimental data is scanty, but it is indicated how observations of the effect could lead to information about molecular properties.