High-Sensitivity Submillimeter-Wave Spectroscopy of Silicon-Containing Interstellar Molecules

在400 ~ 500 GHz频段引入四倍器后，微波光谱仪的有效灵敏度得到了显著提高。对乘法器特性的详细研究表明，四倍器在指定的边缘频率区域提供显著的第五分量输出功率。这使我们能够在500和650 GHz之间的频率区域进行中等灵敏度光谱。我们利用高灵敏度亚毫米波光谱仪结合倍增器研究了几种瞬态分子，特别是星际分子的潜在候选者。探测到新的星际分子：我们将Naobeyama 45 m望远镜在TMC-1和IRC+10216上探测到的几条未识别的谱线定位为两个新的积云和碳分子CH_2CCC和CH_2CC。另外两个自由基，SiN和HCCN，我们首先在实验室检测到其谱线，也通过IRAM和NRAO望远镜的观测被确定为新的星际分子。含硅分子光谱研究：用实验室亚毫米波光谱首次在SiH_4、C_2H_2和CO的混合放电等离子体中检测到C_2H_2Si、CH_2Si和HSiO三种新的含硅瞬态物质。通过分析它们的光谱线，可以得到精确的分子常数，从而得到详细分子结构的基本信息。

The effective sensitivity of the microwave spectrometer was significantly improved by introducing a quadrupler for the 400 to 500 GHz region. A detailed study on the characteristics of the multiplier revealed that the quadrupler gives significant 5th component output power in the edge frequency regions specified. This enables us to carry out moderate-sensitivity spectroscopy in the frequency region between 500 and 650 GHz. We have studied several transient molecules, especially potential candidates for interstellar molecules by using the highsensitivity submillimeter-wave spectrometer combined with the multiplier.1. Detection of new interstellar molecules : We assigned several unidentified lines, which were dbtected toward TMC-1 and IRC+10216 by Naobeyama 45 m telescope, to two new cumulene and carbone molecules, CH_2CCC and CH_2CC. The other two free radicals, SiN and HCCN, whose spectral lines we detected first in the laboratory, were also identified as new interstellar molecules by observations using IRAM and NRAO telescopes.2. Spectroscopy of silicon-containing molecules : Three new silicon-containing transient species, C_2H_2Si, CH_2Si, and HSiO, were detected for the first time in the discharged plasma of a mixture of SiH_4, C_2H_2, and CO with laboratory submillimeter-wave spectroscopy. Their spectral lines were analyzed to give precise molecular constants, from which fundamental information for detailed molecular structures were derived.