Fluorescence of SiO Condensate in Near Infrared Region

在反射星云中，观测到了扩展的红光过量发射(ERE)。这种辐射来自一颗中央恒星辐射的尘埃。作者提出，这种排放可能是由类碳粉尘淬火的香石复合材料(QCC，ApJ1992)引起的。具有Si-O网络结构的尘埃可能存在于反射星云中。本文测量了SiO凝析油的荧光光谱，并讨论了SiO荧光对ERE的贡献。我们制备了三种SiO凝析油材料：(1)由SiO气体沉积而成的SiO凝析油，(2)将SiO凝析油暴露在空气中形成的氧化型SiO凝析油，(3)在真空中将SiO凝析油加热到650℃得到的热蚀变SiO凝析油。在一种系统中，用Ar激光(488.4 nm，2 mW)激发，两种探测器：硅探测器(500-1000 nm)和锗探测器(750-1500 nm)进行检测；另一种系统，用汞-氙灯(313 Nm)激发，用光电倍增器(R666和R376,400-800 nm)和Ge探测器(750-1500 nm)进行检测。在氧化态SiO凝聚体的测量中，利用光电倍增管探测到峰值波长在480-550 nm的微弱黄光发射，根据我们的测量，“SiO凝聚体尘埃”不能作为反射星云中的REE发射体。

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.