EPR spectra and electronic structure of some phosphorus-containing radical ions

Electron paramagnetic resonance of PO 2 2? and SO 2 ? radicals in barite

“…Our studies have shown that Gupta et al (1974) and Krystek (1980) did not interpret their results correctly: we performed a special study of the paramagnetic center in barite having the same principal values of g-tensor as reported by Krystek (1980), but detected no hyperfine structure typical for the SO; radical. The identification of the PO 2-radical in barite given earlier (Bershov 1970) turned out to be inconsistent with our results. In order to obtain a more precise model for this center we plan further investigations.…”

“…A radical believed to be PO22-was found in calcite (Bershov et al 1968, Bershov 1970 as well as in barite (Bershov 1970). The results for the radical described in the present paper differ essentially from those data, but we think we have a definite identification as PO22 -by comparison with the isoelectronic SO~ radical in the same matrix.…”

Theory‐Guided Defect Tuning through Topochemical Reactions for Accelerated Discovery of UVC Persistent Phosphors

“…The formation of oxygen vacancies, either in the synthesis or the postsynthetically topochemical treatment, can be described by the following equation, where the Kröger–Vink notation is used Simultaneous formation of two oxygen vacancies in one [PO 4 ] tetrahedron can result in the occurrence of undercoordinated P–O unit, namely, [PO 2 ]. As shown in Figure a, before X‐ray irradiation the sample shows an ESR signal with g = 2.0002 and a line width of 34 G, which can be assigned to the [PO 2 ] •2− radical that also exists in other phosphorus‐containing compounds . The presence of the [PO 2 ] •2− radicals, due to the removal of two coordinated oxygen atoms from the [PO 4 ] structural units, is in consistence with the PALS result.…”

“…As shown in Figure 5a, before X-ray irradiation the sample shows an ESR signal with g = 2.0002 and a line width of 34 G, which can be assigned to the [PO 2 ] •2− radical that also exists in other phosphorus-containing compounds. [35] The presence of the [PO 2 ] •2− radicals, due to the removal of two coordinated oxygen atoms from the [PO 4 ] structural units, is in consistence with the PALS result. Under X-ray irradiation, constituent atoms in the product interact with X-ray photons, and high-energy electrons are ejected from lattice atoms, accompanied by the creation of holes (process ① in Figure 5b); such ejected high-energy electrons produce secondary…”

“…We chose lanthanum orthophosphate as a model system for our study (Figure S1, Supporting Information), with the idea that it can exhibit various structural defects such as atomic point defects, defect complexes, and radicals, and possess large band gaps that is suitable for UVC afterglow. [30][31][32][33][34][35][36] We began by carrying out first-principles DFT calculations aimed at probing whether such defects hold potential to function as traps required for afterglow. The calculated bandgap of monoclinic LaPO 4 is 5.19 eV ( Figure S2, Supporting Information), relatively smaller than the experimental value of 6.40 eV.…”