Nd induced changes in IR spectra of CaWO4 single crystals

Characterization of MeWO4 (Me=Ba, Sr and Ca) nanocrystallines prepared by sonochemical method

“…Their strongest intensity peaks diffracted from the same plane specified as (1 1 2). They have scheelite structure with tetragonal crystal system [1][2][3]6,16,17] and have I4 1 /a or C 6 4h space-group symmetry [2,15,16]. Calculated lattice parameters [18] for BaWO 4 (a = b = 0.5618 nm, c = 1.2734 nm), SrWO 4 (a = b = 0.5415 nm, c = 1.1962 nm) and CaWO 4 (a = b = 0.5248 nm, c = 1.1394 nm) are very close to those of the corresponding JCPDS cards [15], and have the influence on the spaces between crystallographic planes.…”

“…There are W ions in tetrahedrons composing of O ions. Me ions are surrounded with eight O ions [3]. The properties of MeWO 4 nanocrystallines are influenced by the chemical composition, structure, phase and morphologies.…”

“…The properties of MeWO 4 nanocrystallines are influenced by the chemical composition, structure, phase and morphologies. The tungstates are very useful in a variety of applications, such as scintillators [2,3], stimulated Raman scattering [1], optoelectronic devices [4] and catalysts [5]. They were prepared by a variety of methods, such as a simple templatefree precipitation technique [1], spray pyrolysis [2], microwave-assisted synthesis [5], chemical solution method [6], a facile microemulsion-mediated hydrothermal process [7] and electrochemical method [8].…”

Síntese pelo método da coprecipitação e caracterização estrutural do tungstato de cálcio com estrutura tipo scheelita

“…No espectro vibracional na região do infravermelho, dois modos acústicos (1A u e 1E u ) são inativos enquanto que os modos ópticos B u são proibidos. Por esta razão, apenas 8 vibrações ativas remanescentes, representadas pela Equação (C), são esperadas no espectro infravermelho [33,34]:…”

Crucibleless crystal growth and Radioluminescence study of calcium tungstate single crystal fiber

“…Bulk CaWO 4 single crystals are mostly grown by the Czochralski method [8,9] whose the main disadvantage are the contaminated with the crucible material, besides this growth method can cause strains, cracks, low-angle grain boundaries, gas bubble entrapment, among other undesirable effects in produced crystals [10]. Crucibleless growth techniques could be useful to growth single phase scheelite CaWO 4 , with advantages like geometry and low contamination of shaped crystals.…”