Laboratory high resolution spectroscopy for Interstellar matter in the optical region

弥散星际带(DIB)最早于1922年在恒星的光学吸收光谱中被发现。虽然已经检测到了数百个DIBS，但DIBS仍然是光谱学中最长的悬而未决的问题。目前还不知道什么样的分子具有这些吸收作用。识别DIBS的最好方法之一可以是以下步骤：1)在实验室中产生DIBS候选分子，2)测量分子的电子跃迁频率，3)将频率与天文观测光谱进行比较。为了能够解决DIBS问题，我们开发了一种放电-发射光谱仪系统。中空阴极被用来在放电中产生分子离子，因为有人认为分子离子可能是DIBS起源的候选者。放电由1500V的脉冲电压产生。我们系统的宽波长范围由两台HORIBA Jobin Yvon iHR320(200-800 nm波长范围，使用三个槽密度分别为1200和1800 gr/mm的光栅)和Actron Research Corporation Spectro pro275(可见光-1600 nm波长范围，600 gr/mm)覆盖。用光电倍增管探测并通过锁定放大器(Femto LIA-MV-200-L)记录了弥散的放电-发射。在观察到一次Ar气体放电时，强烈地探测到了Ar离子的光学跃迁，其强度与Ar中性离子的光跃迁强度相当。利用放电中的中空阴极效应可以有效地产生离子。

The diffuse interstellar bands (DIBs) were first discovered in the optical absorption spectra on stars in 1922. Although several hundreds DIBs were detected already, DIBs still remain the longest standing unsolved problem in spectroscopy. It has not been known that what kind molecules have these absorptions. One of the best approaches to identify DIBs can be the following procedure: 1) a generation of a DIBs candidate molecule in laboratory, 2) measurements of frequencies of electronic transitions of the molecule, and 3) comparisons between the frequencies and astronomically observed spectra.To be able to solve the DIBs problem, we have been developed a discharge-emission spectrometer system. A hollow cathode was used to generate molecular ions in a discharge, since it has been suggested that molecular ions can be probable candidates of DIBs origins. The discharge was produced by a pulsed voltage of 1500V. A wide wavelength range of our system was covered by two spectrometers HORIBA Jobin Yvon iHR320 (the 200-800 nm wavelength range using three gratings having groove densities 1200 and 1800 gr/mm) and Actron Research Corporation Spectro pro275 (the visible - 1600 nm wavelength range, 600 gr/mm). The dispersed discharge-emission was detected by a photomultiplier and recorded via the lock-in amplifier (Femto LIA-MV-200-L).In observing a discharge of Argon gas, optical transitions of Argon ion were strongly detected having comparable intensities with those of Argon neutral. The ion can be effectively produced by the hollow-cathode effect in the discharge.