An increase in the Fröhlich-electron-LO-phonon interaction strength with decreasing nanocrystal size in the strong confinement limited is reported. This results from the size dependence of resonant Raman scattering by $\mathrm{Cd}{\mathrm{S}}_x{\mathrm{Se}}_{1-x}$ nanocrystals embedded in a glass slab. The mean particle radius $20<\mathrm{}\overline{R}<30\mathrm{}$ Å increases monotonically with the position along the slab so that, for each laser line, the resonance has been tuned by scanning the sample with a microprobe. The relative strength between Fröhlich and deformation-potential contributions is determined by analyzing the polarization properties of the scattering.

Fluorophlogopite, a new F-dominant mineral of the mica group, was found at Monte Calvario, Biancavilla, lower southwestern flanks of Mt. Etna volcano (Catania, Sicily, Italy). The mineral occurs in autodasts of gray-red altered benmoreitic lavas, primarily associated with fluoro-edenite, alkali-feldspars, clino- and ortho-pyroxenes, fluorapatite, hematite, and pseudobrookite. It was formed by metasomatism of the original lava rocks from very hot fluid enriched in F, Cl, and other incompatible elements. Fluorophlogopite occurs as very thin laminae with a diameter of 200 to 400 μm. Main physical properties are pale yellow in color; yellowish-white in thin section; vitreous to resinous luster; transparent; non-fluorescent; Mohs’ hardness 2–3; brittle and malleable; perfect cleavage on {001}; biaxial (−), α_calc = 1.5430(8), β= 1.5682(5), γ = 1.5688(5) (λ = 589 nm); 2V_meas = 17(2)°; α = acute bisectrix ⊥ (001); nonpleochroic; D_calc = 2.830 g/cm³ (using empirical formula and single-crystal unit-cell parameters), D_calc = 2.842 g/cm³ (using empirical formula and powder cell constants). Infrared spectrum did not show a significant absorption band in the OH-stretching region (3800–3600 cm^−l) confirming that the F content of the fluorophlogopite from Biancavilla is close to the stoichiometric value. Unit-cell parameters from X-ray powder-diffraction data (114.6 mm diameter Gandolfi camera, CuKα) are a = 5.305(2), b = 9.189(3), c = 10.137(4) Å, β = 100.02(3)°. These data agree with those obtained by single-crystal X-ray studies on a very thin (~15 μm) fluorophlogopite crystal, i.e., Monoclinic (1M polytype); Space Group C2/m; a = 5.3094(4), b = 9.1933(7), c = 10.1437(8) Å, β = 100.062(5)°, V= 487.51(6) A³, Z = 2. Structure refinements using anisotropic displacement parameters converged at R = 3.50, R_w = 4.37, R_sym = 3.72%. Electron microprobe analysis performed on the same crystal used for X-ray investigation gave: SiO₂ = 45.75(39), TiO₂ = 1.05(5), A1₂O₃ = 9.60(19), MgO = 27.92(30), MnO = 0.16(3), FeO_tot = 1.25(6), BaO = 0.09(5), K₂O = 8.22(11), Na₂O = 0.61(30), Cl = 0.02(1) wt%. Secondary Ion Mass Spectrometry (SIMS) was used to estimate light elements [Li₂O = 0.30(1) and H₂O = 0.16(2) wt%] and fluorine content [F = 8.69(24) wt%]. The new mineral fluorophlogopite and its name were approved by IMA-CNMMN (2006/011).