Spectroscopic Study on Non-Fluorescent Radicals and Reaction Dynamics of Rare-Gas Metastables with Molecules

为了阐明稀有气体可燃物与分子的反应动力学，对非氟自由基的光谱检测进行了研究。用于产生稀有气体可燃物的放电源和反应室被差分泵浦。反应产生的自由基通过共振增强多光子电离（REMPI）电离，并通过飞行时间质谱仪（Reflectron）检测。本文采用准分子激光（XeCl）泵浦染料激光器，采用空心阴极放电和脉冲放电两种放电源进行了REMPI。利用原放电源进行了首次实验。测量了苯、环庚三烯酚酮和水分子的REMPI谱，考察了仪器的灵敏度。我们尝试观察了反应（1）和（2）产生的CH_2和CH_2自由基的（2+1）和（3+1）REMPI谱，反应（1）为Ar（^3P_<2，0>）+CH_4->CH_3+H+Ar（1）->CH_2+H_2（2 H）+Ar（2）。然而，我们没有成功地观察到REMPI谱。然后，我们将放电源改为脉冲型。与空心阴极放电源相比，产生了更高浓度的氩亚稳原子。本文测量了Ar（^3P_<2，0>）与CCl_4反应中CCl自由基的REMPI谱。我们还测定了Ar（^3P_<2.0>）与CH_4、卤代甲烷和硅烷反应生成电子基态双原子自由基的截面。

Spectroscopic study has been perfomed for the detection of non-fluo-rescent radicals, in order to clarify the reaction dynamics of rare-gas metastables with molecules. Discharge sources for generation of rare-gas metastables and the reaction chamber were differentially pumped. The radicals produced by the reactions were ionized via resonant enhanced multiphoton ionization (REMPI) and were detected by the time-of-flight mass spectrometer (Reflectron). Exicimer laser (XeCl) pumped dye laser was used for REMPI.Two types of discharge sources, a holow cathode discharge and pulsed discharge were used. The first experiments were carried out by using the former discharge souurce. REMPI spectra of benzene, tropolone and water molecules were measured for examining the sensitivity of the apparatus. We have attempted to observe (2+1) and (3+1) REMPI spectra of CH_2 and CH_2 radicals which are produced from reactions (1) and (2), respectively, Ar(^3P_<2,0>)+CH_4->CH_3+H+Ar (1) ->CH_2+H_2(2H)+Ar (2). However, we did not succeed in observing REMPI spectra. Then, we have changed the discharge source to the pulsed type. Argon metastable atoms were produced in higher concentration compared with the hollow cathode discharge source. Measurement of REMPI spectra of CCl radical was carried out for reaction of Ar(^3P_<2,0>) with CCl_4. We have tried to enhance the sensitivity of the new apparatus.Furthermore, we detetermined the cross sections for the formation of diatomic radcals in their clectronic ground states which were produced from the reactions of Ar(^3P_<2.0>) with CH_4, halomethanes and silanes.