High field dielectric measurements in water

High field dielectric measurements of the “Piekara factor” have been carried out for pure water at 293 K. The measurements have been made possible by the development of a new technique capable of measuring permittivity changes Δε/ε as low as 10–5 in samples with conductivities as high as 10–2Ω–1 m–1. Reproducible results with water having conductivities in the range 1 to 4 × 10–5Ω–1 m–1 gave Δε/E2=–(1.00 ± 0.15)× 10–15 m2 V–2. The results are interpreted in terms of the low field dipole polarization factor Rp and the non-linear field effect correlation factor RS. The behaviour is that of the “classical” non-linear effect of a negative Δε due to permanent dipoles.