English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A broad (FWHM ≈ 7300 cm -1 ) intense band at ~21 700 cm -1  in the optical absorption spectra of natural Fe 2+ , Fe 3+ -rich garnets is attributed to electronic intervalence charge-transfer transitions (IVCT), VIIIFe 2+  + VIFe 3+  → VIIIFe 3+  + VIFe 2+ . In Fe 3+ , Fe 2+ -bearing garnets of predominantly almandine compositions, this band causes yellowish tinges in addition to the pink color, typical of pure Fe 3+ -free almandines. In garnets from deeper-seated mafic granulites from kimberlite pipes in Siberia with high skiagite (Fe 3  2+ Fe 2  3+ Si 3 O 12 ) contents, IVCT causes intense brownish-yellow colors. The relatively high energy of the band (~21 700 cm -1 ) compared to diverse minerals showing IVCT between Fe 2+  and Fe 3+  in adjacent octahedral sites, is attributed to the charge-transfer transition taking place between Fe 2+  and Fe 3+  in non-equivalent, dodecahedral and octahedral sites of the garnet structure. Band intensity is directly correlated with the product of Fe 2+  and Fe 3+  as measured by Mössbauer spectroscopy. The energy of the IVCT band is nearly independent of temperature, whereas its intensity decreases slightly with increasing temperature. Pressure induces a weak shift of the band to lower energies, Δν/ΔP ≈ -75 cm -1 /GPa, but intensity of the bands remains practically unchanged. Such temperature and pressure dependencies are quite different from those in other minerals showing IVCT between Fe 2+  and Fe 3+  in equivalent octahedral positions of structure.

american mineralogist

Optical absorption study of natural garnets of almandine-skiagite composition showing intervalence Fe 2+  + Fe 3+  → Fe 3+  + Fe 2+  charge-transfer transition