~(22)Na正电子湮没对D-、L-苯丙氨酸不对称作用的研究

    • 摘要: 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。

       

      Abstract: ASYMMETRICALINTERACTIONSOF22NaPOSITRONSWITHD┐,L┐PHENYLALANINESWangWenqingDingXiangLinFeng(DepartmentofTechnicalPhysics,PekingUniversity,Beijing100871)WangYunyuCaoHuimin(InstituteofHighEnergyPhysics,ChineseAcademyofSciences,Beijing100039)ABSTRACTTheaimofthisworkliesinsearchingtherelationbetweenasymmetryofD-,L-pheny-lalaninesandpositroniumformation.ThepurityofthesublimedD-,L-phenylalaninesischeckedbyFT-IR.TherelativequantumeficiencyissamefortheD-,L-isomers.Thesam-plesarepressedcarefulytotabletsof13.0mmdiameterand2.0mmthicknesswiththesamerigorouspressure.Foreachsample,thelifetimespectrumismeasuredfor8times.Thespectraaredecomposedtothreecomponents.Thelongestoneatributedtopositroniumoftripletstate(o-Ps).Theexperimentalresultsshowthatboththeτ3andI3areabithigherinD-isomerthaninL-isomer.Theτ3are(1.570±0.033)nsand(1.529±0.033)nsinD-,L-phenylalaninesrespectively,andtheI3are(10.107±0.315)%and(8.457±0.379)%.Itmeansthatthepositronsseemtoformmorepositroniums(o-Ps)inD-PhethaninL-PhebyaI3,d/I3,Lfactorof1.195.KeywordsPositronannihilation22NaD-,L-PhenylalanineAsymmetricalinter-action

       

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