^(22)Na正电子湮没对D-、L-苯丙氨酸不对称作用的研究

ASYMMETRICAL INTERACTIONS OF 22 Na POSITRONS WITH D , L PHENYLALANINES

研究２２Ｎａ正电子湮没与Ｄ－、Ｌ－苯丙氨酸（Ｐｈｅ）的不对称相互作用。用傅立叶红外光谱检测Ｄ－、Ｌ－两种异构体的升华样品纯度，异构体有一致的吸收曲线。实验数据显示在Ｄ－Ｐｈｅ中三重态正电子素ｏ－Ｐｓ的寿命τ３和强度Ｉ３都比Ｌ－Ｐｈｅ的大。Ｄ－Ｐｈｅ的τ３值为（１．５７０±０．０３３）ｎｓ，Ｉ３值为（１０．１０７±０．３１５）％；Ｌ－Ｐｈｅ的τ３值为（１．５２９±０．０３３）ｎｓ，Ｉ３值为（８．４５７±０．３７９）％。结果表明，正电子在Ｄ－Ｐｈｅ中比在Ｌ－Ｐｈｅ中形成更多的三重态正电子素，Ｄ－Ｐｈｅ和Ｌ－Ｐｈｅ的Ｉ３比值为１．１９５。

The aim of this work lies in searching the relation between asymmetry of D , L phenylalanines and positronium formation.The purity of the sublimed D , L phenylalanines is checked by FT IR.The relative quantum efficiency is same for the D , L isomers.The samples are pressed carefully to tablets of 13 0 mm diameter and 2 0 mm thickness with the same rigorous pressure.For each sample,the lifetime spectrum is measured for 8 times.The spectra are decomposed to three components.The longest one attributed to positronium of triplet state (o Ps).The experimental results show that both the τ 3 and I 3 are a bit higher in D isomer than in L isomer.The τ 3 are (1 570±0 033)ns and (1 529±0 033)ns in D , L phenylalanines respectively,and the I 3 are (10 107±0 315)% and (8 457±0 379)%.It means that the positrons seem to form more positroniums (o Ps) in D Phe than in L Phe by a I 3, d /I 3, L factor of 1 195.