The phonon spectrum of crystalline tellurophene-d0 and tellurophene-d4

Abstract

The phonon spectra of tellurophene-d0 and tellurophene-d4 at 75 K have been studied and the exciton splittings of the fundamental modes have been assigned. The spectra are in accord with centrosymmetric factor group predictions, assuming a Cs site symmetry and a [Formula: see text] space group. In the circumstances, crystals of tellurophene have four molecular units per unit cell and become isomorphous with other aromatic heterocyclic crystals. Two-phonon processes, revealed for thick samples, are associated with internal + internal and internal + external combinations. Some of these last are accounted for by K ≠ 0 critical points selection rules.