Laboratory submillimeter-wave spectroscopy of interstellar deuterated molecules : evolution timescale determination of dark cloud cores

星际氘化分子的实验室亚毫米波光谱：暗云核心的演化时间尺度测定

基本信息

批准号：
12440161
负责人：
SAITO Shuji
金额：
$ 10.37万
依托单位：
Fukui University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

The main subject of the present proposal is high-sensitivity submillimeter-wave spectroscopy of interstellar deuterides, aiming to estimate the chemical evolutionary age of dark cloud cores from the degree of deuterium fractionation. The following results are obtained during three years proposed.1. The present high-sensitivity submillimeter-wave spectrometer covering up to 600 GHz was improved to cover a new frequency region of 500-830 GHz, aided by the present Grant-in Aid and other sources. The new spectrometer was used to study a few interstellar deuterides given below.2. The proposed method of estimating the chemical evolutionary age of dark cloud cores from the degree of deuterium fractionation is applied to two dark cloud cores, cyanopolyyne peak and ammonia peak, of Taurus Molecular Cloud 1, using the abundance ratios between DC0^+ and HCO^+ combined with the new standard model network of gas-phase chemical reactions. The difference in deuterium fractionation between the two cor … More es is explained by a time difference in the evolutionary age of more than 10^5 yr. This is the first example of the chemical evolutionary age of dark cloud cores estimated from the degree of deuterium fractionation.3. The method proposed above is also applied to two cloud cores, the northeast NH_3 core and the southern NH_3 core, of L134N which is a typical dark cloud having no energy sources. An analysis including the degree of deuterium fractionation and C/0 depletion in cores shows that the southern core is in a more evolved stage than the northeast core. The C/0 depletion also indicates the degree of core evolution. The existence of highly fractionated NH_2D and NHD_2 recently detected at the southern core is consistent with the high C/0 depletion in the southern core.4. Two interstellar deuterides, HDC1^+ and PHD were studied with a new high-sensitivity submillimeter-wave spectrometer. Spectral patterns of PHD were very complicated due to fine and hyperfine structures of phosphorus, hydrogen and deuterium nuclei. A detailed analysis of complicated spectral lines resulted in a precise determination of the hyperfine coupling constants of phosphorus, hydrogen, and deuterium. The principal axis and principal values of the magnetic dipole coupling tensors of hydrogen in PH_2 and deuterium in PD_2 were derived from the observed values of PHD, PH_2 and PD_2. The principal axis of the hydrogen magnetic coupling tensor in PH_2 makes an angle of 2.3^0 with the PH bond. This result is one of rare cases in which a relation between the hyperfine coupling tensor and the related chemical bond is clearly indicated. Less

本提案的主要主题是星际氘代码的高敏化波光谱，旨在估算氘级分馏程度的乌云核的化学进化年龄。在提议的三年内获得以下结果1。目前覆盖高达600 GHz的高敏率亚毫米波光谱仪得到了改善，以覆盖500-830 GHz的新频率区域，并在当前的授予IN AID和其他来源的帮助下。新的光谱仪用于研究以下给出的一些星际氘代。2。通过使用DC0^+和HCO^+之间的抽象比结合了新的标准模型网络的气体化学化学反应，提出了从氘分馏程度估算乌云分馏程度的化学进化年龄的方法，该方法应用于两个乌云核，即cyanopolyne峰和氨峰，Taurus Molecular云1。两个COR之间的氘分馏的差异是通过超过10^5年的进化年龄的时间差来解释的。这是根据氘分离程度估计的乌云核的化学进化年龄的第一个例子。3。上面提出的方法还应用于L134N的两个云核，即东北NH_3核心和南部NH_3核心，这是一个没有能源的典型的暗云。一项分析包括核心分馏的程度和核心中的C/0深度表明，南部核心的进化阶段比东北核心更具进化。 C/0深度还表示核心演化的程度。最近在南部核心检测到的高度分数的NH_2D和NHD_2的存在与南部核心中的高C/0深度一致。4。两个星际氘化，HDC1^+和PHD进行了研究，并具有新的高敏度亚毫米波光谱仪。由于磷，氢和核核核的细细结构，博士的光谱模式非常复杂。对复杂光谱线的详细分析导致对磷，氢和氘的高精细偶联常数的精确确定。 pH_2中氢偶联的磁偶极耦合张量的主要轴和PD_2中氘的主值源自PHD，PH_2和PD_2的观察值。 pH_2中氢磁耦合张量的主要轴与pH键的角度为2.3^0。该结果是罕见的情况之一，在这种情况下，明确指出了超精细偶联张量与相关化学键之间的关系。较少的