Vitali Nagirnyi

An investigation of the electronic structure of K ₂ SiF ₆ based on GW theory and photoelectron spectroscopy reveals that Auger–Meitner decay of K 3p holes is energetically forbidden in this material.

Scalable synthesis route to highly textured Zn ₂ SiO ₄ films enabling sustainable deep UV emitters.

We present the time-resolved luminescence end station developed at the FemtoMAX beamline at the MAX IV Laboratory for the studies of ultrafast energy relaxation and emission properties. The instrument consists of a temperature-controlled vacuum chamber sample environment, in which the UV–visible luminescence is collected from the point of interaction of ultrashort x-ray pulses with luminescent material and directed to a monochromator equipped with an ultrafast MCP-PMT detector operating in a photon-counting mode. The instrumental response function of the setup, determined by the duration of x-ray pulses (50 fs), optical path, and fast MCP-PMT response, was measured to 32 ps (FWHM) within the spectral range of 200–700 nm. In this paper, we present the results obtained under different operational conditions on the basis of three well-known scintillating samples, demonstrating that this instrument development for the scintillator community has established the foundation for ultrafast luminescence studies at FemtoMAX.

The paper presents a comprehensive description of the construction features of the P66 beamline at the PETRA III storage ring as well as the experimental possibilities offered by this unique facility to the research community. The beamline is dedicated to time-resolved photoluminescence spectroscopy experiments that require high flux, high energy resolution and pulsed excitation at ultrahigh vacuum conditions. The excitation photon energies available at the beamline cover the range from 3.7 to 40 eV with two Al- and Pt-coated diffraction gratings in normal incidence geometry. Two secondary monochromators equipped with several detectors are used to register the photoluminescence signal in the spectral range from 115 to 1200 nm. The pulsed nature of the synchrotron radiation at PETRA III allows the accumulation of luminescence decay kinetics within a time interval of 192 ns (timing mode) or 16 ns (brightness mode) with a time resolution of 130 ps. Time-resolved luminescence spectroscopy studies are performed using the method of time-correlated single photon counting. The paper also reviews recent advances, as well as the most common and important scientific cases of experimental research conducted at the beamline. Plans for the future development of the beamline, along with the expansion of experimental capabilities and the implementation of additional applications of the facility, are discussed.

This study explored the influence of Sc3+ ions incorporation on the structural, vibrational, luminescent, and scintillation properties of Pr3+-doped Lu3(Al, Sc)2.5Ga2.5O12 garnet crystals. Addressing the limited research on Sc-admixed and Pr3+ doped garnet systems, this work successfully demonstrated the crystallization of garnet crystals from the melt, overcoming the substantial atomic mismatch between Sc and Al while preserving the thermodynamic stability of the garnet phase. Importantly, Sc-admixing enhanced atomic homogeneity and allowed for increased doping concentrations of Pr3+ ions, which is crucial for tailoring the functional properties of advanced optical materials. The trap depths ranged from 1.63 eV (deep traps) to 0.22 eV (shallow traps) across all samples, with frequency factors predominantly between 1 × 107 and 1 × 1011 s–1, consistent with first-order thermoluminescent kinetics. From a materials design perspective, Sc3+ ions substitution induced beneficial host lattice disorder, enhancing the emission intensity of 4f15d11 → 4f2 interconfigurational and 4f2 → 4f2 intraconfigurational transitions. This effect highlighted the potential of Sc as a promising substituent for enhancing the luminescence intensity of rare earth elements. Synchrotron radiation experiments provided insights into the impact of Sc on band gap energy and energy transfer efficiency toward Pr3+ ions offering new opportunities for engineering scintillators and phosphors with tunable optical properties.