The UV absorbance bands of dibenzo-p-dioxin (dibenzo-1,4-dioxin, DD) are investigated by synchrotron radiation linear dichroism (SRLD) spectroscopy on molecular samples aligned in stretched polyethylene. The investigation covers the range 58000–30000 cm^–1 (170–330 nm), thereby providing new information on the transitions of DD in the vacuum UV region. The observed polarization data enable experimental symmetry assignments of the observed transitions, leading to revision of previously published assignments by Ljubić and Sabljić (J. Phys. Chem. A 109 (2005) 8209-8217). In general, the experimental spectra are well predicted by the results of quantum chemical calculations using time-dependent density functional theory (TD–DFT). The observed absorbance in the region 58000–55000 cm^–1 (170–180 nm) in the vacuum UV is almost entirely short-axis polarized, in pleasing agreement with the predicted spectrum.

通过同步辐射线性二色性（SRLD）光谱法研究了在拉伸聚乙烯中排列的分子样品中二苯并-对二恶英（dibenzo-1,4-dioxin，DD）的紫外吸收带。研究覆盖了58000–30000 cm ^–1（170–330 nm）范围，从而提供了有关真空紫外区域中DD跃迁的新信息。所观察到的极化数据使得能够对所观察到的跃迁进行实验对称分配，从而导致由Ljubić和Sabljić修改了先前发表的分配（J. Phys。Chem。A 109（2005）8209-8217）。通常，通过使用依赖于时间的密度泛函理论（TD-DFT）的量子化学计算结果，可以很好地预测实验光谱。在58000-55000 cm区域内观察到的吸光度真空紫外光中的^–1（170–180 nm）几乎完全是短轴偏振的，与预测的光谱相符。