Pyroelectricity and Asymmetric Thermal Vibrations of Atoms in Minerals

Abstract

A structural approach was attempted to estimate rigid ion contributions to pyroelectric coefficients, employing atomic position vectors determined in the least-squares refinement of a polar mineral, cancrinite. The two sets of positions, obtained from the centers of gravity (centroids) and modes of asymmetric probability density functions (pdf) of atoms, were applied to calculate electric polarizations, whose temperature derivatives may correspond to the rigid ion contributions to the pyroelectric coefficient, γ^(σ), normally measured under the condition of constant stresses and to the secondary pyroelectric coefficients, γ⁽²⁾, respectively. The primary pyroelectric coefficient γ^(ε) was given as the difference γ^(σ)-γ⁽²⁾.