Basic Studies of Chemical Reaction at Very Low Temperature

4.2K时，隧道反应P-H_2(J=0)+H的速率常数约为o-H_2(J=1)+H的3倍。P-H_2固体中H原子主线的ESR线宽是n-H_2固体中H原子主线宽度的1/3。结果表明，固体H_2中的H原子被捕获在置换位，而固体HD和D_2中的H(D)原子被捕获在间隙八面体位置。在4.2K下，90%以上的反冲T原子与氢原子在固体氢中发生热原子反应。在20K下，含苯乙醇的脉冲辐解观察到苯阴离子的宽吸收带，而在77和120K观察到环己二烯自由基的吸收光谱，这表明质子转移反应是C6H6^-+C2H5OH*C6H7+C2H5O^-。研究了高能电子辐照冰在8-77K温度范围内的发射。在40和77K下的发射光谱在380 nm附近出现最大值，在8和20K下在330 nm附近出现最大值。后者是本研究中发现的一个新的发射带。

The rate constant for the tunneling reaction P-H_2(J=0)+H was about three times as large as that for o-H_2(J=1)+H at 4.2K. The ESR linewidth of the main line of H atoms in the p-H_2 solid was one-third in the n-H_2 solid. Comparison of the observed ESR line-widths with theoretical ones shows that H atoms in solid H_2 are trapped in substitutional sites, while H(D) atoms in solid HD and D_2 are trapped in interstitial octahedral sites.Reactions of recoil tritium (T) atoms were studied in solid H_2-D_2 mixtures at 4.2K. Formation of HT is due to hydrogen atom abstraction by recoil T atoms from H_2 and D_2. More than 90% of recoil T atoms react with hydrogen by a hot atom reaction in solid hydrogen at 4.2K.A broad optical absorption band of benzene anions was observed by pulse radiolysis of ethanol containing benzene at 20K, while an absorption spectrum of cyclohexadienyl radicals was observed at 77 and 120K, indicating the proton transfer reaction C_6H_6^-+C_2H_5OH * C_6H_7+C_2H_5O^-. Emission of high-energy-electron-irradiated ice was studied over the temperature range 8 - 77K. The emission spectra at 40 and 77K show a maximum around 380nm, while they show a maximum around 330nm at 8 and 20K. The latter band is a new emission band found in this study.