It has been established that optical properties of BaSO₄ powder undergo significant degradation under the action of the solar-spectrum simulating xenon lamp radiation. The cause of such degradation is the presence of intrinsic defects that absorb the solar spectrum quanta with the energy lower than the width of BaSO₄ band gap. Preheating at 400 °C for 2 h leads to sintering of powder grains and to the removal of the precipitated water decomposition products, which block the defects’ relaxation. Additionally, the heating makes the radiation stability higher.

中文翻译：

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太阳光谱定量作用下影响BaSO ₄粉末光学性能退化的因素

已经确定，在模拟氙气灯辐射的太阳光谱的作用下，BaSO ₄粉末的光学性能显着降低。造成这种退化的原因是存在固有缺陷，这些缺陷以低于BaSO ₄带隙宽度的能量吸收太阳光谱量子。在400°C下预热2小时会导致粉末颗粒烧结，并去除沉淀的水分解产物，从而阻碍了缺陷的松弛。另外，加热使辐射稳定性更高。