Abstract
The temperature derivative of birefringence in the crystallographic ac plane of carbazole is calculated as a function of molecular rotations and translations in the ac plane. The experimental thermal expansion and effective polarizabilities deduced from the crystal refractive indices are used; for comparison, the polarizability is also derived from an empirically modified INDO calculation. The effect of molecular rotation on the birefringence is particularly sensitive to the polarizability anisotropy, but the effect of translations is not. The birefringence depends linearly on rotation and on translation along the a direction, but quadratically on translation along c. The internal displacements cannot be determined uniquely from the single measured birefringence derivative, but could be determined given the other two birefringence derivatives. 29 refs.
| Original language | English |
|---|---|
| Pages (from-to) | 181-191 |
| Number of pages | 11 |
| Journal | Molecular Crystals and Liquid Crystals |
| Volume | 73 |
| Issue number | 3-4 |
| Publication status | Published - Sept 1981 |