The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have...The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have been determined.A high optical quality single crystal of dimention 4.5 mm has been grown,which is the largest one as we know so far.The micro-hardness of Na_5Eu(WO_4)_4 single crystal is 3.46×10~3 MPa.Its refractive index is 1.81 in white light wavelength region and the specific gravity is 5.65 g/cm^3.The fluorescent and excitation spectra have been determined and the reason of the fluorescent quench of ~5D_2 and ~5D_1 to ~7F_j of Eu^(3+)can be explained as multi-phonon non-radiation transition.展开更多
Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have bee...Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have been analysed by means of the site group analysis method of group theory.The experimental vibrational modes have been assigned to A_g,B_g,E_g,A_u and E_u of crystal factor group C_(4h).Because the energies of stretching vibrational modes of(WO_4)^(2-)ion groups are very high(in the range of 755～940 cm^(-1)),multiphonon nonradiative transitions of ~5D_2→~5D_1 and ~5D_1→~5D_0 in Eu^(3+)will occur.So it causes Eu^(3+)ions in Na_5Eu(WO_4)_4 to emit ~5D_0→~5F_j(j=1,2,3,4)emissions mainly at room temperature and the emission light of Na_5Eu( WO_4)_4 has high red colour purity.展开更多
文摘The single crystal growth of stoichiometric host luminescent crystal Na_5Eu(WO_4)_4 has been investigated. Using Na_2WO_4 as a flux,the optimum conditions to grow a pure single crystal by flux-slow-cooling method have been determined.A high optical quality single crystal of dimention 4.5 mm has been grown,which is the largest one as we know so far.The micro-hardness of Na_5Eu(WO_4)_4 single crystal is 3.46×10~3 MPa.Its refractive index is 1.81 in white light wavelength region and the specific gravity is 5.65 g/cm^3.The fluorescent and excitation spectra have been determined and the reason of the fluorescent quench of ~5D_2 and ~5D_1 to ~7F_j of Eu^(3+)can be explained as multi-phonon non-radiation transition.
文摘Raman and infrared spectra of host luminescent crystal Na_5Eu(WO_4)_4 in several different geometric con- figurations have been investigated.The symmetrical species of lattice vibrational modes of the crystal have been analysed by means of the site group analysis method of group theory.The experimental vibrational modes have been assigned to A_g,B_g,E_g,A_u and E_u of crystal factor group C_(4h).Because the energies of stretching vibrational modes of(WO_4)^(2-)ion groups are very high(in the range of 755～940 cm^(-1)),multiphonon nonradiative transitions of ~5D_2→~5D_1 and ~5D_1→~5D_0 in Eu^(3+)will occur.So it causes Eu^(3+)ions in Na_5Eu(WO_4)_4 to emit ~5D_0→~5F_j(j=1,2,3,4)emissions mainly at room temperature and the emission light of Na_5Eu( WO_4)_4 has high red colour purity.
