压力对GdoBr:Eu晶场参数的影响

 在室温下测量了GdoBr:Eu的常压和高压荧光谱，光谱范围在13 000~21 500 cm^-1之间，压力至12 GPa。由光谱数据得到了Eu³⁺晶场能级随压力的变化曲线。⁷F_0～5能级随压力的变化规律比较复杂，而⁵D_0~2各能均随压力的升高几乎线性地降低。在基态谱项⁷F的49个状态上进行了晶场拟合计算，所得常压下的5个非零晶场参数分别为：B₀²＝-1 124.0 cm^-1，B₀⁴＝-969.6 cm^-1，B₄⁴＝827.9 cm^-1，B₀⁶＝889.6 cm^-1，B₄⁶＝377.0 cm^-1。高压下的计算结果表明，B₀⁴、B₀⁶这两个晶场参数随压力的增加而增大，B₄⁶随压力的增加而减小，而B₀²、B₄⁴随压力的变化有些起伏。晶场强度在8 GPa以下随压力增加而减小，其后开始变强。

INFLUENCE OF HIGH PRESSURE ON CRYSTAL FIELD PARAMETERS FOR GdOBr:Eu

The fluorescence spectra of GdOBr:Eu at room temperature and under high pressure up to 12 GPa were measured and analyzed. 43 lines were observed at ambient pressure in the wavenumber of 13 000～21 500 cm^-1. From the fluorescence spectra, the major part of the ⁷F_0～5 and all the ⁵D_0~2 stark levels were determined. Under pressures, the ⁵D_0~2 stark levels shift downwards, but the ⁷F_0～5 stark levels shift upwards or downwards irregularly. The crystal field simulation calculation is conducted on the 49 ⁷F states. The five nonzero crystal field parameters obtained at ambient pressure are as follows: B₀²=-1 124.0 cm^-1, B₀⁴=-969.6 cm^-1, B₄⁴=827.9 cm^-1, B₀⁶=889.6 cm^-1 and B₄⁶=377.0 cm^-1. Under high pressures, B₀⁴ and B₀⁶ increase with pressure. While B₄⁶ decreases with pressure, B₀² and B₄⁴ show somewhat irregular variations with perssure. From the crystal field parameters, crystal field strength S was deduced. At ambient pressure, S =445.0 cm^-1. Under high pressures it decreases with pressure till about 8 GPa, then increases with pressure till 12 GPa.