Conformation of p-terphenyl under hydrostatic pressure

摘要

The conformation of p-terphenyl (C_(18)H_(14)) and deuterated P-terphenyl (C_(18)D_(14)) has been investigated, using high-pressure infrared spectroscopy at liquid-helium temperatures. First-principles calculations, together with the experimental results, were performed to determine the structure of p-terphenyl in the twisted conformation. At low temperatures and pressures, p-terphenyl belongs to the C_2 point group of symmetry. In this configuration, the central ring is twisted with respect to the plane of the outer rings. The symmetry of the molecule is nearly C_(2h), consistent with previous x-ray diffraction measurements.