Far Infrared Spectroscopy of Molecular Ions and Short-lived Molecules using frequency tunable CW sources

安装了微波电源、毫瓦频标系统和直流放电电源，搭建了稳频&lt；CO_2&gt；激光器。未来几年将研制的&lt；CO2&gt；激光器和微波电源与另一台国产&lt；CO2&gt；激光器将使用非线性元件MIM二极管产生频率可调的连续远红外辐射。我们利用微波电源、频标、直流放电电源、自制放电室、InSb探测器和倍频器，构建了一台高灵敏度的毫米波和亚毫米光谱仪。光谱仪的灵敏度足以研究分子离子、自由基和星际分子。所获得的结果总结如下。1)。首次观测到电子激发态&lt；a^1&gt；&lt；Delta&gt；(&lt；T_e&gt；=12000&lt；cm^(-1)&gt；)的微波光谱，精确测定了其详细的分子常数。2)首次测定了&lt；HbF^+&gt；，&lt；H_3&gt；&lt；S^+&gt；和&lt；H_2&gt；&lt；Cl^+&gt；的纯转动光谱。&lt；H_3&gt；&lt；S^+&gt；是含硫星际分子化学中的关键分子，预计星际空间中也存在&lt；H_2&gt；&lt；Cl^+&gt；。3)。通过实验室微波光谱分析，确定了一种新的含硫碳链分子CCS和&lt；C3&gt；S的两个成员。根据得到的详细分子常数，我们对Nobeama射电天文台的45m射电望远镜和贝尔电话实验室的7m射电望远镜观测到的14条不明星际谱线进行了归属。特别是包括U45379在内的7条最强未知线中的4条归属于ccs自由基的跃迁，3条归属于&lt；C_3&gt；S分子。

We installed a microwave power source, a MW frequency standard system, and a dc discharge power supply, and constructed a frequency stabilized <CO_2> laser. The <CO_2> laser and microwave power source combined with another <CO_2> laser which will be home-made in the coming years will be used to generate frequency tunable CW far infrared radiation by using a non-linear element, MIM diode.We constructed a high-sensitivity millimeter and submillimeter spectrometer, using the microwave power source, the frequency standard, the dc discharge power supply, a home made discharge cell, an InSb detector, and a frequency multiplier. The sensitivity of the spectrometer is high enough to study molecular ions, free radicals, and interstellar molecules. The results obtained are summarized below. 1). The microwave spectrum of the NF radical in the electronically excited state <a^1> <DELTA> ( <T_e> = 12000 <cm^(-1)> ) was observed for the first time and its detailed molecular constants were precisely determined. 2).The pure rotational spectra of <HBF^+> , <H_3> <S^+> , and <H_2> <Cl^+> were detected for the first time. <H_3> <S^+> is a key molecualr ion in the chemistry of sulfur-containing interstellar molecules and <H_2> <Cl^+> is also expected to exist in interstellar space. 3). Two members of a new sulfur-containing carbon-chain molecules, CCS and <C_3> S, were detected by laboratory microwave spectroscopy. The detailed molecular constants obtained made us to assign fourteen unidentified interstellar lines observed by 45m radio telescope of Nobeyama Radio Observatory and by 7m telescope of Bell Telephone Laboratory. Particularly four of seven strongest unidentified lines including U45379 were assigned to the transitions of the CCS radical and three to the <C_3> S molecule.