磁場(chǎng)方向平行對(duì)手性丙氨酸晶體的電子自旋性影響

磁場(chǎng)方向平行對(duì)手性丙氨酸晶體的電子自旋性影響

1通道pcr-pch-pch-pch-pch-pcen-alin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-roin-4,3.3.3.3.3.3.3.3.3histoperation四氟-4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,7.4,5.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3,5.5.5.5.5.5.3.3.3,5.5.5.5.3.3.3,5.5.5.5.5.5.5.5.3.3.3.3.3.3.4,5.5.5.5.5.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.3.d-andl-galm，第1行，d-二級(jí)，微十字異常，第2行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第1行，微十字異常，第10-5ev微十字異常，第5個(gè)區(qū)域的微聯(lián)系區(qū)域和第1個(gè)區(qū)域的微甜點(diǎn)。2utealcoholcoluhendurachiurachisondx-n-rakiurachiwellingurachipholgatching,u2004和9-11re持續(xù)保護(hù)/價(jià)值管理性別ThepolycrystallinepowdersofD-andL-alanine(SigmaChemicalCo.)aretwicerecrystallizedfromsterilizationaqueoussolutionat277Kbyslowevaporationfor2to3weeks,producingwellformedcrystalelongatedalongthecaxisandwithprincipalfaces{110}6,7washedwithdroppingabsolutealcohol,evacuatedandkeptinadesiccator.BothchiralalaninecrystalsaredeterminedbyX-raydiffraction(XRD)crystallographyonaRigakuRAXIS-RAPIDimagingplatediffractometerwithgraphitemonochromatedMo-Karadiation(λ=0.071069nm)at300,270,250K8andneutrondiffractiondatafromcrystalsat60,240,250,260,295,300K,9-11respectivelyThecrystalpuritywasidentifiedbythepositive-ionelectrospraymassspectra(EI-MS)withadetectionlimitof2fmoloforganicimpurity.12TheenantiomericpurityofD-andL-alaninesinglecrystalswereidentifiedbygaschromatographymassspectrometry(GC-MS)oftheirN-trifluoroacetyl(TFA)isopropylestersonChirasil-Valcapillarycolumns.13Fouriertransforminfrared(FTIR)spectrometer(NicoletiN10MXUSA)withadetectionlimitof10mgwasprecludedthepossibleH2Ocontentinthemeasuringalaninecrystals.3影響的神圣迪迪斯運(yùn)營(yíng)3.1u3000litecolitchsfig.3ThemassmagneticsusceptibilityofD-andL-alaninesinglecrystalswasmeasuredwithaQuantumMPMSXL-5SQUIDsystemfrom2to330KbyDirectCurrent(dc)OptionTwocrystalswereselected(massof390.89mgforD-alanineand338.50mgforL-alanine)andrectangularlymountedinthelongplastictube.Thecrystalswereplacedthatthecaxiswasexactlyparalleltothedirectionoftheappliedfield.Basedonthecalculationoftheorientationalpotentialenergy,anexternamagneticinductionB=±1Twasappliedandthenthedc-magneticsusceptibilitywasmeasuredbyscanningthreetimes.Wehavefoundanelectronspin-fliptransitionofN+H…O-hydrogenbondundermagneticinduction+1TinD-alanineand-1TinL-alaninealongc(z)axis(Fig.1).Basedonthemagneticsusceptibilitymeasurements(Fig.1)andneutrondiffractiondata(Fig.2),weconsiderthephasetransitionmechanism:first,themagneticdipolemomentofN+H…O-hydrogenbondmightbeassociatedwithmotionofchargesinthenucleus.Themagnitudeofsuchamagneticdipolemomentwouldbeoftheorderofe?/2M,whereMisthemassofaproton,?=h/2π(hisPlanckconstant).Butthemagneticdipolemomentmeasuredexperimentallyfromthesizeofsplittingisoftheorderofμb=e?/2m,wheremisthemassofanelectron,whichisabout2000timeslarger.Therefore,thenucleuscannotberesponsiblefortheobservedmagneticdipolemoment.Itssourcemustbetheelectron.Second,theelectronsofhydrogenatomhaveanintrinsicangularmomentumcalledspin,andanassociatedspinmagneticdipolemoment.Becausetheelectronhasanegativecharge,itsmagneticdipolemomentμlisantiparalleltoitsorbitalangularmomentumL.14Whenitisplacedinanexternalmagneticfieldof+1T,themagneticdipolewilltendtoalignwiththefield.Theorientationalpotentialenergywhenthedipoleisparalleltothefieldis-μlB,anditis+μlBwhenthedipoleisantiparalleltothefield.Sotheenergythatmustbesuppliedtoturnthedipoleis2μlB=2×9.27×10-24×1=1.85×10-23J=1.16×10-4eVConversely,thedipoleN+H…O-ofL-alanineisoriginallyalignedantiparalleltothefield,itcannotturntoalignitselfparalleltothefieldunlessitcangetridofthesameamountofenergy.ThisexperimentprovedthattheelectronofhydrogeninN+H…O-bondisspin-up(↑)paralleltothec(z)axisinD-alaninebutspin-down(↓)antiparalleltothec(z)axisinL-alanineunderexternalmagneticfieldof+1T,andviceversaunder-1T.Wefindthetruechiralityandparity-time(PT)asymmetryofN+H…O-hydrogenbondinzwitterionicmodelanddiscoverthatthequintessentialtrulychiralinfluenceisthehelicityofthelatticestructureofpeptidebond.Thisistheeasywaytosolvethepuzzleof“falsechirality”oftranslatingandrotatingammoniamodelofCompton.15Additionally,themeasurementsofthespecificheat16evidencefortheelectronspin-fliptransitionofN+H…O-hydrogenbondofD-/L-alaninecrystalat272.02K/271.85Kwiththeheatoftransitionof1.87J·mol-1/1.46J·mol-1,respectively.TheenergydifferencebetweenD-andL-alaninecrystalsis(1.87-1.46)J·mol-1=4.2×10-6eV·molecule-1,whichisapproximativelycoincidentwithdc-magneticsusceptibilitymeasurementinexternalmagneticfieldof+1TinD-alanineand-1TinL-alanine.Sincespinisaxialvector,alltheaboveresultsarenotseenfromthepolycrystallinepowdermeasurements.3.2paramagneting.3.4回血書paramageningWeusethesamecrystals(390.89mgforD-alanineand338.50mgforL-alanine)tostudythemagneticpropertiesunderstrongmagneticinductionB=5TwithaquantumdesignmodelMPMS-7SQUAD-basedmagnetometerfrom5to330KbyReciprocatingSampleOption(RSO).Inthemeasurements,D-alaninemanifestsemergentparamagnetismat297.6K(Figs.3(a),4(a)).HoweverinL-alanine,whenthefieldreachesacriticalvaluethereisadiscontinuityinthemagnetizationthemomentsflopfirstlyperpendiculartothefield,asthefieldreachesavaluehighenough,thenanelectronspin-flopstatetoparamagneticstatetransitionisobservedaround303.9K(Figs.3(b),4(b)).WehavefoundemergentparamagnetisminD-andL-alaninecrystalswithdifferentprocess.ThemagneticinteractionenergyundermagneticinductionB=5TisμbB=9.27×10-24×5=4.635×10-23J=2.893×10-4eVkBT=1.38×10-23×300=4.140×10-21J=2.586×10-2eV,sothat,μbB/kBT=2.893×10-4/2.586×10-2=1.12×10-2Hence,μbBbeingabout1.12%ofkBT.AssumingthatμbB<kBTisvalidatroomtemperatureundermagneticinductionof5Telectronspin-floptoparamagneticstatetransitionisoccurred.D-alanine:kBTD=8.617×10-5×297.6=2.564×10-2eVL-alanine:kBTL=8.617×10-5×303.9=2.619×10-2eVkB(TL-TD)=8.617×10-5×6.3=5.428×10-4eVAccordingtotheparamagneticsusceptibilitydata,D-alanine(390.89mg):TD=297.6K,M=3.377×10-7emu,L-alanine(338.50mg):TL=303.9K,M=4.589×10-7emu,Thedifferenceofmassparamagneticsusceptibilitycanbeestimated:Asthefieldreachesavaluehighenoughof5T,theparamagnetismisconservedatafixedtemperaturerangewarmingfrom297.6to310Kandcoolingfrom309to5K.Thisisthesaturatedcondition,inwhichallthespinswiththeirindividualmagneticdipolemomentarealigned.Whentheappliedfieldisremoved,thethermalmotionrandomizesthedipoledirectionssothatthemagnetizationiszero(Fig.5).4u3000chi-au4.3.4.4.4.4與4.5.5.5.5.5.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.5.5.5.5.5.5.5.4.5.4.5.4.5.4.5.4.5.5.4.5.4.5.5.5.5.5.5.5.5.5.5.5.5.4.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.5.4.5.4.5.5.4.5.4.5.4.5.5.5.5.5.5.5.5.5.5.5.5.5.5.4.5加入了非負(fù)商業(yè)聯(lián)邦h.4.3.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.5.5.4.5.4.5.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.4.5.4.3.4.3.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.5.4.4.4.4.4.4.3.4.3.4.3.4.3.4.3.4.3.4.4.5.4.5.4.5.Thefield-dependentmagneticpropertiesofchiralalaninecrystalsassociatedwithelectronicmotionsareinvestigatedThekeyfindingistheobservationofspin-orbitalseparationinthequasi-one-dimensionalN+H…O-hydrogenbondofL-andD-alaninecrystals.TherequirementforparamagnetisminchiralalaninecrystalsisthatthedipolemomentsofN+H…O-hydrogenbondhavesomedegreeofisolation.Thehallmarkofone-dimensionalphysicsisabreakingupoftheelementaryelectronintoitssepa