Trial production of molecular beam Fourier transform microwave spectrometer designed for solid organic molecule.

本项目的目的是试制一种灵敏的分子束傅里叶变换微波光谱仪，用于高沸点有机固体或液体的测量。我们改进了现有谱仪的喷嘴设计，使之更容易产生固体与氩气的混合分子束，首先改变分子束的方向，使之与微波传播方向平行。这种改进是在Grabow（基尔U.，德国）和Lovas（NIST，USA）。由于反射镜的背面朝向真空室的外部，利用本项目购置了微波放大器和镜频抑制混频器，通过提高微波输入功率和降低微波电路噪声来提高灵敏度，并在此基础上构造了一个双凹面镜法布里-珀罗腔（直径550毫米）两年，当我们得到以前的赠款。本项目的目的是确定生物分子与水形成的复合物的分子结构。我们试着测定了苯甲酸-水、邻苯二酚-水、苯甲醚-水这几种络合物的光谱，但都观察不到谱线。用从头算方法估算了苯甲酸-水配合物的结构。

The purpose of this project is a trial production of a sensitive molecular beam Fourier transform microwave spectrometer designed to measure of organic solid or liquid with high boiling point. We improved the nozzle design of our existing spectrometer to make it easier to produce a mixed molecular beam of solid with argon.As the first step we changed the direction of molecular beam to be parallel to that of microwave propagation. This improvement is after Grabow (Kiel U., Germany) and Lovas (NIST, USA). As the back of the mirror faces to the outer of the vacuum chamber, the handling of solid sample become easy.We purchased by this grant the microwave amplifier and the image rejection mixer to improve the sensitivity by increasing of inlet microwave power and reducing the noise of the microwave circuit.As the second step we are constructing a Fabry-Perot cavity having two concave mirrors (550mm diameter) for two years when we got the previous grant. We constructed the tool for polishing the mirrors with low price.Our purpose of this project is to determine a molecular structure of the complex between biomolecule and water. We tried to the measure spectra of these complex ; benzoic acid〜water, catechol〜water, anisol〜water, however we can not observe the spectral lines. We estimated the structure of benzoic acid〜water complex by ab initio calculation.