FEATURES IN THE SPECTRA OPTICAL ABSORPTION OF FILAMENTOUS CRYSTALS β-PbN6

10.25712/ASTU.1811-1416.2022.01.004

Abstract

At the developed microspectrophotometric installation, which implements the principle of immobility of a filamentous crystal (FC) in the optical path, absorption spectra were measured at the same crystal site, both in the photochemical decomposition (PCD) mode and under the action of a strong electric field in a vacuum microcryostat located on the optical axis, at temperatures from liquid nitrogen to 600 K. A number of features were established, depending on both the thickness of the NK β-azide of lead (β-PbN₆) and spectral mode of photometry. When photometring from the ultraviolet region to the infrared region at wavelengths of 490 nm and above, negative absorption (luminescence) is observed, which is absent in spectrophotometry from the infrared region. The feasibility of Buger's law for wavelengths at which the manifestation of the centers of color is observed has been confirmed. The volumetric distribution of absorption centers has been proven. The influence of temperature, deformation, photo- and electrofield effects on the absorption spectra of light polarized in mutually perpendicular planes E_||[010] and E_┴[010]. The thermal coefficient of change in the width of the band gap zone (GZ) of NK (β-PbN₆) was established and its width was determined, which practically coincides with the width of the GZ determined earlier in α-azide of lead). The actual defective nature of the centers of fundamental absorption in the region of 367-375 nm was proved.