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Radiochromic films are used as position-sensitive dose meters in e.g.medical physics and radiation processing. The currently available films like those based on lithium-10,12-pentacosdiynoate or leucomalachite green are either toxic or non-reusable, or both. There is thus a great need for a sustainable solution for radiochromic detection. In the present work, we present a suitable candidate: hackmanite with the general formula Na8Al6Si6O24(Cl,S)2. This material is known as a natural intelligent material capable of changing color when exposed to ultraviolet radiation or X-rays. Here, we show for the first time that hackmanites are also radiochromic when exposed to alpha particles, beta particles (positrons) or gamma radiation. Combining experimental and computational data we elucidate the mechanism of gamma-induced radiochromism in hackmanites. We show that hackmanites can be used for gamma dose mapping in high dose applications as well as a memory material that has the one-of-a-kind ability to remember earlier gamma exposure. In addition to satisfying the requirements of sustainability, hackmanites are non-toxic and the films made of hackmanite are reusable thus showing great potential to replace the currently available radiochromic films.

“Glow-in-the-dark” materials are known to practically everyone who has ever traveled by airplane or cruise ship, since they are commonly used for self-lit emergency exit signs. The green afterglow, persistent luminescence (PeL), is obtained from divalent europium doped to a synthetic strontium aluminate, but there are also some natural minerals capable of afterglow. One such mineral is hackmanite, the afterglow of which has never been thoroughly investigated, even if its synthetic versions can compete with some of the best commercially available synthetic PeL materials. Here we combine experimental and computational data to show that the white PeL of natural hackmanite is generated and controlled by a very delicate interplay between the natural impurities present. The results obtained shed light on the PeL phenomenon itself thus giving insight into improving the performance of synthetic materials.

In this work, we designed a simulation protocol to investigate the spectroscopic properties of point defects in sodalite minerals, Na8Si6Al6O24Cl2, using time-dependent density functional theory. The F-center absorption spectrum and the sulfur impurity’s (S2–) fluorescence spectrum were simulated by considering different electrostatic environments around the cluster (embedded cluster model, ECM approach) and by coupling the electronic transition with vibrations obtained at the periodic boundary condition (PBC) level. These results highlight the influence of vibronic coupling in these spectra and of the confinement in the case of S2–fluorescence. The performances of 17 density functionals were assessed for the calculation of vertical excitation and emission energies against experimental values; global hybrids and generalized gradient approximation (GGA) gave the best results. The impact of chemical composition on the absorption spectra of the F-center was investigated, allowing the simulation of colors in absorption for 12 materials from the sodalite family.