Developments of Optical Spectrometers as Approaches to Diffuse Interstellar Bands. Issue Volume 9:Issue S297(2013) (21st February 2014)

• Record Type: Journal Article
• Authors: Araki, M.; Uchida, S.; Kondo, N.; Matsushita, Y.; Abe, K.; Ito, K.; Tsukiyama, K.
• Is Part Of: Proceedings of the International Astronomical Union. Volume 9:Issue S297(2013)
• Page Start: 291
• Page End: 293
• Publication Date: 2014-02-21
• Subjects: methods: laboratory, -- techniques, -- astrochemistry, -- plasmas; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921313016013
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: A discharge-emission spectrometer and a cavity ringdown spectrometer have been developed to aid in the solution to the diffuse interstellar band (DIB) problem. A hollow cathode was used to generate molecular ions in a discharge because it has been suggested that molecular ions are probable DIB candidates. The discharge was produced by a pulsed voltage of 1300–1500 V. A wide wavelength range of optical emission from the discharge was examined by a HORIBA Jobin Yvon iHR320 monochromator. The dispersed discharge emission was detected by a photomultiplier and was recorded via a lock-in amplifier. The 2 B 3 u – X 2 B 2 g electronic transition of the butatriene cation H2 CCCCH2 + was observed in the discharge emission of 2-butyne H3 CCCCH3 . The frequency of the electronic transition was measured to be 20381 cm −1, and a comparison study was made with known DIB spectra. The resolution of the discharge-emission spectrometer is insufficient to make precise comparisons between laboratory frequencies and astronomically observed DIB spectra. We therefore developed the cavity ringdown spectrometer using the same hollow cathode. The high sensitivity of this spectrometer was confirmed by the observation of the forbidden band of O2 .