Calculation of the Band Gap Energy and Study of Cross Luminescence in Alkaline-Earth Dihalide Crystals

Abstract

The band gap energy as well as the possibility of cross luminescence processes in alkaline-earth dihalide crystals have been calculated using the ab initio Perturbed-Ion (PI) model. The gap is calculated in several ways: as a difference between one-electron energy eigenvalues and as a difference between total energies of appropriate electronic states of the crystal, both at the HF level and with inclusion of Coulomb correlation effects. In order to study the possibility of ocurrence of cross luminescence in these materials, the energy difference between the valence band and the outermost core band for some representative crystals has been calculated. Both calculated band gap energies and cross luminescence predictions compare very well with the available experimental and theoretical results.

Orbital-free molecular dynamics study of melting inK20,K55Aguado1 2001Phys. Rev. BSelf Cite18151View full textAdd to dashboardCite

“…The melting behavior of these disordered structures has been separately analyced and found to be different from that of icosahedral clusters. 32 As the comparison with experiment was favourable only for icosahedral isomers and the total energy of these structures was always lower than that of disordered structures, we have chosen icosahedral isomers in the study of the melting behavior of large alkali clusters: K 55 , Rb 55 and Cs 55 are complete two-shell icosahedrons, K 92 and K 142 are incomplete three-shell icosahedrons constructed by following the icosahedral growing pattern described by Montejano-Carrizales et al 33 The low-temperature isomer of K 20 was obtained by the dynamic simulated annealing technique, 14 by heating the cluster to 400 K and then slowly reducing the temperature. The resulting structure is essentially the same as that obtained for Na 20 with the same technique.…”

Scintillation properties of improved 5% Eu2+-doped BaCl2 single crystal for X-ray and γ-ray detection

“…The band gap of BaCl 2 has been reported with values ranging from 6.7 to 8 eV [16][17][18]; therefore, according to Eq. (1), the crystals of BaCl 2 should have a luminosity of 63,000-75,000 ph/MeV using b¼2, S and Q¼1 [19].…”

Trends in Search for Bright Mixed Scintillators

“…The correlation between ( L ex /L veg ) max and the band gap difference Δ E g basing on E g values is plotted in Figure . Despite the strong LY enhancement in garnets and some halides with Δ E g > 0.9, large positive deviations of LY were observed as well in systems with weak E g changes.…”