Fluorescence of SiO Condensate in Near Infrared Region

在反射星云中，观测到延伸的红色过量发射（ERE）。辐射来自被中心恒星辐射的尘埃。作者提出，碳质粉尘可能是由类似淬灭的碳质复合材料引起的（QCC, ApJ1992）。具有Si-O网状结构的尘埃可能在反射星云中存在。在这项工作中，我们测量了SiO凝聚物的荧光光谱，并讨论了SiO荧光对ERE的贡献。我们制作了三种SiO冷凝材料；(1)由SiO气体沉积而成的SiO冷凝物，(2)将SiO冷凝物暴露于空气中而成的SiO冷凝物氧化，(3)将SiO冷凝物在真空中加热至650℃而成的SiO冷凝物热蚀变。用两种光谱系统测量了SiO凝聚态材料的荧光光谱；在一个系统中，使用Ar激光器（488.4 nm, 2mW）进行激发，并使用Si探测器（500-1000 nm）和Ge探测器（750-1500 nm）两种探测器进行检测；在另一个系统中，使用Hg-Xe灯（313nm）进行激发，并使用光倍增器（R666和R376, 400-800 nm）和Ge探测器（750-1500 nm）两种探测器进行检测。在未经处理的SiO凝结物和热改变的SiO凝结物的荧光测量中，我们没有检测到明显的发射。在氧化SiO凝结物的测量中，利用光倍增器检测到微弱的黄色发射，峰值波长在480 ~ 550 nm。根据我们的测量，“SiO凝聚尘埃”不可能是反射星云中ERE发射器的候选者。

In reflection nebulae, extended red excess emission(ERE)are observed. The emission is come from the dust irradiated with emission of a central star. Authors proposed the emission can be caused by the carbonaceous dust alike quenched carvonaceous composite(QCC, ApJ1992). A dust, which has Si-O network structure, may exit in reflection nebulae. In this work, we measured fluorescence spectra of SiO condensates and discussed contribution of the SiO fluorescence to the ERE.We made three kinds of SiO condensate materials ; (1) SiO condensate which was made as a deposit from SiO gas, (2) oxidize SiO condensate which was made with an exposure of the SiO condensate to air, (3) thermally altered SiO condensate which was made with heating of the SiO condensate to 650 C in vacuum.We measured fluorescence spectra of the SiO condensate materials with two spectroscopy systems ; in one system, Ar laser (488.4 nm, 2mW)is used for excitation and two kinds of dectors, Si detector (500-1000 nm)and Ge detector(750-1500 nm), are used for detection and in the other system, Hg-Xe lamp (313nm)is used for excitation and two kinds of dectors, photo-multiplier (R666 and R376, 400-800 nm)and Ge detector (750-1500 nm), are used for detection.In both fluorescence measurements of untreated SiO condensate and thermally altered SiO condensate, we did not detect obvious emission. In the measurement of oxidized SiO condensate weak yellow emission with a peak wavelength at 480-550 nm was detected with using the photo-multipliers.According to our measurement, the "SiO condensate dust" cannot be a candidate of the ERE emitter in the reflection nebulae.