A New Gas Chromatography Mass Spectrometer Equipped with a Hyperthermal Surface Ionization as a Ion Source

介绍了一种以超热表面电离（HSI）系统为离子源的新型气相色谱-质谱联用系统。HSI是超声分子束（SMB）中的分子加速和表面电离（SI）的组合。为了考察各种参数对系统工作特性的影响，本文研究了HSI的电离机理，在第1篇文章中，我们将"γ因子"定义为用于电离的动能的分数，并通过两个独特的Ek和Ts与测量的离子电流的关系估算，其中Ek是分子动能，Ts是表面温度。两种独立的方法估算的γ值相当一致。推导出的结论是：（1）动能部分用于电离，（2）能量转换效率（γ值）因分子而异，（3）表面电离所需的能量与电离能（IE）和表面功函数（ψ）的差异引起的能隙有关，在第2号文章中，描述了一种估算用于激发分子中振动度的分子动能的转化率的方法。实验结果表明：（1）动能部分用于激发振动能级，其转化率约为30%。(2)总速率约为初始动能转化为分子内能的50%。(3)表面热能转化为分子内能的可能性很小，本文综述了有机物表面电离的最新进展。这包括（1）基本原理，（2）仪器，（3）响应特性和（4）应用。

A new gas chromatography-mass spectrometer system equipped with a hyperthermal surface ionization (HSI) system as an ion source is described. The HSI is a combination of molecular acceleration in supersonic molecular beam (SMB) and surface ionization (SI). To examine the effect of various parameters on operational characteristics of this system, ionization mechanism of HSI was studied.In the article No.1, we defined the "γ-factor" as the fraction of the kinetic energy used for ionization, and was estimated from two unique Ek and Ts correlation with measured ion current, where, Ek is the molecular kinetic energy and Ts is the surface temperature. The γ values estimated from the two independent methods agreed fairly well. Deduced conclusions are : (1) the kinetic energy is partially used for ionization, (2) the efficiency of energy conversion (γ value) varies from molecule to molecule, (3) the energy required for surface ionization is associated with the energy gap due to the difference in ionization energy (IE) and the surface work function (ψ).In the article No.2, a method to estimate the conversion rate of the molecular kinetic energy used for the excitation of the vibrational degrees in the molecule is described. The experimental results obtained by this method led to the following conclusions : (1) The kinetic energy is partially used for excitation of the vibrational degree, and the conversion rate amount to some 30 %. (2) The total rate amounts to some 50 % of the initial kinetic energy converted to the internal energy of the molecule. (3) There is only a very small probability of surface thermal energy being transferred to the internal energy of the molecule.The article No.3 summarizes the recent development in surface ionization (SI) of organics. This includes (1) basic principles, (2) instrumentation, (3) response characteristics, and (4) applications.