AN IONIC GROUPING THEORY OF THE ELECTRO-OPTICAI AND NON-LINEAR OPTICAL EFFECTS OF CRYSTALS (Ⅱ)——A THEORETICAL CALCULATION OF THE SECOND HARMONIC OPTICAL COEFFICIENTS OF THE LITHIUM IODATE CRYSTAL BASED ON A HIGHLY DEFORMED OXYGEN-OCTAHEDRA MODEL I

Abstract

A highly deformed oxygen-octahedra group (IO3)-1 such as that found in the iodate has been adapted te explain the second harmonic optical coefficients of the LiIO3 crystal. Calculations have been made on the basis of such an ionic grouping model. Calculated values are in good agreement with the experimental ones, hence the following conclusions:1) The second harmonic optical effects of the iodate crystal arise mainly from the covalent-bond contribution of the ionic grouping (IO3)-1. 2) Within this (IO3)-1 grouping it is the lone-pair electronic orbitals and the |2σ>, |2Py> orbitals of oxygen which have particulas influence on these second harmonic optical effects.