MAGNETIC FIELD EFFECT OF SPIN DYNAMICS IN THE RECOMBINATION PROCESS OF SHORT-LIVED ION-PAIRS INDUCED BY IRRADIATION

目前主要研究了几种氟化甲苯辐照诱导的短寿命离子对复合过程中的自旋动力学。讨论了复合过程中单重态和三重态产率与磁场的关系，并首次利用光学探测电子自旋共振（ODESR）观测到的信号确定了2,3,4 -三氟甲苯自由基阴离子的超精细耦合常数。本实验使用的样品为五氟甲苯、八氟甲苯、2,3,4-三氟甲苯和α、α、α -三氟甲苯的角鲨烷溶液，其中含有作为发光敏化剂的paterphenyl。采用90 muCi^<90>Sr作为辐射源，在配备微波放大器的传统x波段ESR光谱仪上观测ODESR光谱。发现每种样品的发光率分别与浓度、温度和磁场有关。发现ODESR信号的强度与它们的依赖性有关。它们之间的关系可以用离子对密度、离子对寿命、超精细耦合常数、自旋-晶格弛豫时间T_1和自旋-自旋弛豫时间T_2来解释。特别是，荧光产率对磁场的依赖关系可以根据B.Brocklehurst提出的计算进行定性解释。这表明离子对寿命与T_1之间的关系对荧光产率的磁场依赖性很重要。

The spin dynamics in recombination process of the short-lived ion-pairs induced in some kinds of fluorinated toluene by irradiation have been studied mainly in the current year. The magnetic field dependence of the yield of the singlet and triplet state in the recombination process also was discussed, Moreover, the hyperfine coupling constant of the radical anion of 2, 3, 4-trifluoro toluene was determined for the first time by the signal observed by optically detected electron spin resonance (ODESR).The samples used in this experiment were squalane solutions of penta-fluoro toluene, octa-fluoro toluene, 2,3,4-trifluoro toluene and alpha, alpha, aopha-trifluoro toluene in which included paterphenyl as a luminescent sensitizer.90 muCi^<90>Sr was used as the radiation source, ODESR spectrum was observed with the conventional X-band ESR spectrometer equipped a micro-wave amplifier.It is found that the luminescence yield for every sample depends on the concentration, temperature and magnetic field, respectively. The intensity of ODESR signal was found to be related to their dependences. The relation between them can be explained by the terms of the density of ion-pairs, the life-time of ion-pairs, the hyperfine coupling constant, spin-lattice relaxation time T_1 and spin-spin relaxation time T_2. In particular, the magnetic field dependence of the fluorescence yield can be explained qualititatively based on the calculation proposed by B.Brocklehurst. This suggests that the relation between the life-time of the ion-pairs and T_1 is important for the magnetic field dependence of the fluorescence yield.