Wonke umntu uyazi ukuba amanzi avela kwiindawo ezintathu zokudibanisa. Sibeka i-kettle, kwaye amanzi aqala ukubilisa kwaye aphephe, aguquke kwi-liquid ukuya kwi-gaseous. Siyibeka efrijini, kwaye iqala ukujika ibe yiqhwa, ngaloo ndlela isuka kwi-liquid ukuya kwindawo eqinile. Nangona kunjalo, phantsi kweemeko ezithile, umphunga wamanzi okhoyo emoyeni unokudlula ngokukhawuleza kwisigaba esiqinileyo, udlula isigaba solwelo. Siyazi le nkqubo ngesiphumo sayo - iipatheni ezintle kwiifestile ngemini yasebusika eneqabaka. Abathandi bemoto, xa bekhuhla umkhenkce kwi-windshield, bahlala bebonakalisa le nkqubo ngokusebenzisa inzululwazi kakhulu, kodwa i-epithets eneemvakalelo kunye necacileyo. Ngandlela-thile, iinkcukacha zokubunjwa komkhenkce omacala mabini zagqunywa ekusithekeni iminyaka emininzi. Kwaye kutshanje, okwesihlandlo sokuqala, iqela lezazinzulu lamazwe ngamazwe liye lakwazi ukubona ukwakheka kweathom yomkhenkce omacala mabini ngexesha lokuyilwa kwawo. Zeziphi iimfihlo ezifihliweyo kule nkqubo ilula ebonakalayo, izazinzulu zakwazi njani ukuzityhila, kwaye ziluncedo njani iziphumo zazo? Ingxelo yeqela lophando iya kusixelela malunga noku. Hamba.
Isiseko sophando
Ukuba siyabaxa, ngoko ke phantse zonke izinto ezisijikelezileyo zinamacala amathathu. Nangona kunjalo, ukuba siqwalasela ezinye zazo ngocoselelo ngakumbi, sinokufumana ezine-dimensional. Uqweqwe lomkhenkce olwenzeka kumphezulu wento ethile ngumzekelo obalaseleyo woku. Ubukho bezo zakhiwo akusiyo imfihlo kuluntu lwezenzululwazi, kuba ziye zahlalutywa ngamaxesha amaninzi. Kodwa ingxaki yeyokuba kunzima ukuba nomfanekiso ngqondweni wezakhiwo ezinemetastable okanye eziphakathi ezibandakanyekayo ekwenziweni komkhenkce we-2D. Oku kubangelwa iingxaki ze-banal - i-fragility kunye ne-fragility yezakhiwo ezifundwayo.
Ngethamsanqa, iindlela zanamhlanje zokuskena zivumela iisampuli ukuba zihlalutywe ngempembelelo encinci, evumela ukuba idatha ephezulu ifunyenwe ngexesha elifutshane, ngenxa yezizathu ezingentla. Kolu phononongo, izazinzulu zasebenzisa i-microscopy yamandla e-atom engadibaniyo, kunye nencam yenaliti ye-microscope eqatywe nge-carbon monoxide (CO). Indibaniselwano yezi zixhobo zokuskena yenza kube nokwenzeka ukufumana imifanekiso yexesha lokwenyani yezakhiwo zomphetho we-bilayer ene-hexagonal ice ekhule kumphezulu wegolide (Au).
I-Microscopy ibonise ukuba ngexesha lokuqulunqwa komkhenkce omacala amabini, iindidi ezimbini zemiphetho (amacandelo adibanisa ii-vertices ezimbini zepolygon) ngaxeshanye zihlala kwisakhiwo sayo: i-zigzag (i-zigzag)zigzag) kunye nesitulo (isitulo seengalo).
I-Armchair (ekhohlo) kunye ne-zigzag (ekunene) imiphetho usebenzisa igraphene njengomzekelo.
Kweli nqanaba, iisampulu zakhawuleza zaba ngumkhenkce, zivumela ulwakhiwo lwe-athomu ukuba luhlolwe ngokweenkcukacha. Imodeli nayo yenziwa, iziphumo zazo zihambelana kakhulu neziphumo zokujonga.
Kwafunyaniswa ukuba kwimeko yokubunjwa kweembambo ze-zigzag, i-molecule yamanzi eyongezelelweyo yongezwa kumda okhoyo, kwaye yonke inkqubo ilawulwa yi-bridging mechanism. Kodwa kwimeko yokubunjwa kweembambo ze-armchair, akukho molecule ezongezelelweyo ezifunyenweyo, eziphikisana kakhulu neengcamango zendabuko malunga nokukhula kwe-ice-layer hexagonal ice kunye ne-dimensional hexagonal substances ngokubanzi.
Kwakutheni ukuze izazinzulu zikhethe imakroskopu yamandla e-atom engadibaniyo ukuze ziqwalaselwe endaweni yokuskena i-microscope (STM) okanye i-electron microscope (TEM) yothumelo? Njengoko sele sisazi, ukhetho luhambelana nobunzima bokufunda ixesha elifutshane kunye nezakhiwo ezinqabileyo ze-ice-dimensional ice. I-STM sele isetyenziselwe ukufunda ii-ices ze-2D ezikhule kwiindawo ezahlukeneyo, kodwa olu hlobo lwe-microscope alukhathali kwindawo ye-nuclei, kwaye incam yayo inokubangela iimpazamo zokucinga. I-TEM, ngokuchaseneyo, ibonisa ngokugqibeleleyo ubume be-athomu yeembambo. Nangona kunjalo, ukufumana imifanekiso ekumgangatho ophezulu kufuna ii-electron zamandla aphezulu, ezinokutshintsha ngokulula okanye zide zitshabalalise ubume bomphetho bemathiriyeli ye-XNUMXD edityaniswe ngokudibeneyo, singasathethi ke ngemiphetho ebopheleleke ngakumbi kumkhenkce we-XNUMXD.
I-microscope yamandla e-athomu ayinayo into engalunganga, kwaye i-CO-coated tip ivumela ukufundwa kwamanzi adibeneyo kunye nefuthe elincinci kwiimolekyuli zamanzi.
Iziphumo zophando
Umfanekiso #1
Umkhenkce onamacala amabini wakhuliswa kumphezulu we-Au(111) kubushushu obumalunga ne-120 K, kwaye ubukhulu bawo bebuyi-2.5 Γ (1).
Imifanekiso ye-STM yomkhenkce (1c) kunye nomfanekiso okhawulezayo weFourier wokuguqula (ukufakwa ngaphakathi 1) bonisa ulwakhiwo olulungelelanisiweyo lwe-hexagonal kunye ne periodicity ye-Au(111)-β3 x β3-30Β°. Nangona inethiwekhi yeselula edibeneyo ye-H ye-ice ye-2D ibonakala kumfanekiso we-STM, i-topology ecacileyo yezakhiwo ezinqamlekileyo kunzima ukuyiqonda. Ngelo xesha, i-AFM ene-frequency shift (Ξf) yendawo yesampulu efanayo yanika imifanekiso engcono (1d), okwenza kube lula ukujonga amacandelo e-chair-shape kunye ne-zigzag yesakhiwo. Ubude obupheleleyo bazo zombini iinguqu ziyathelekiseka, kodwa umndilili wobude bembambo yangaphambili bubude kancinane (1b). Iimbambo ze-Zigzag zinokukhula ukuya kuma-60 Γ ubude, kodwa ezimise okwesitulo zigqunywe ziziphene ngexesha lokubunjwa, okunciphisa ubude bazo obuninzi ukuya kwi-10-30 Γ .
Okulandelayo, umfanekiso we-AFM ocwangcisiweyo wenziwa kwiindawo eziphakamileyo zeenaliti (2).
Umfanekiso #2
Kowona mphakamo uphezulu wencam, xa isignali ye-AFM ilawulwa ngamandla aphezulu e-electrostatic, iiseti ezimbini ze-β3 x β3 sublattices kumkhenkce webilayer onamacala amabini zichongiwe, enye yazo iboniswe 2 (khohlo).
Kwimiphakamo yenaliti esezantsi, izinto eziqaqambileyo zale subarray ziqala ukubonisa indlela, kwaye enye i-subarray ijika ibe yinto enobume be-V (2a, iphakathi).
Ubuncinci bokuphakama kwenaliti, i-AFM ibonisa isakhiwo se-honeycomb kunye nemigca ecacileyo edibanisa ii-sublattices ezimbini, ezikhumbuza i-H-bonds (2a, ekunene).
Ubalo lwethiyori yoxinaniso olusebenzayo lubonisa ukuba umkhenkce onamacala amabini okhule kumphezulu we-Au(111) uhambelana nolwakhiwo oludibeneyo lomkhenkce olumaleko-mbini (2s), equka izaleko ezimbini ezimcaba ezinamacala amathandathu zamanzi. I-hexagons yamaphepha amabini adibeneyo, kwaye i-angle phakathi kwee-molecule zamanzi kwi-plane yi-120 Β°.
Kwinqanaba ngalinye lamanzi, isiqingatha seemolekyuli zamanzi zilele ngokuthe tye (ngokuhambelana ne-substrate) kwaye esinye isiqingatha silala ngokuthe nkqo (i-perpendicular to substrate), kunye ne-O-H enye ekhomba phezulu okanye ezantsi. Amanzi angqengqe ngokuthe nkqo kumaleko omnye anikela nge-H-bond kumanzi axwesileyo komnye umaleko, okukhokelela kulwakhiwo olugcweleyo olumile okwe-H.
Ukulinganisa kwe-AFM kusetyenziswa i-quadrupole (dz 2) incam (2b) ngokusekelwe kulo mzekelo ungentla uvumelana kakuhle neziphumo zovavanyo (2a). Ngelishwa, ukuphakama okufanayo kwamanzi okuthe tye kunye nokuthe nkqo kwenza ukuchongwa kwabo kube nzima ngexesha lokucinga nge-STM. Nangona kunjalo, xa usebenzisa i-microscopy yamandla eathom, iimolekyuli zazo zombini iindidi zamanzi zibonakala ngokucacileyo (2a ΠΈ 2b ekunene) kuba ulungelelwaniso oluphezulu lwamandla e-electrostatic lunovakalelo kakhulu kujongwe kwiimolekyuli zamanzi.
Kwakhona kube nokwenzeka ukugqiba umkhomba-ndlela we-O-H wamanzi axwesileyo nathe nkqo ngokusebenzisana phakathi komgangatho ophezulu wamandla e-electrostatic kunye ne-Pauli repulsive forces, njengoko kubonisiwe yimigca ebomvu 2 ΠΈ 2b (embindini).
Umfanekiso #3
Kwimifanekiso 3 ΠΈ 3b (Inqanaba loku-1) libonisa imifanekiso ye-AFM eyandisiweyo ye-zigzag kunye ne-armchair fins, ngokulandelanayo. Kwafunyaniswa ukuba i-edge ye-zigzag ikhula ngelixa igcina isakhiwo sayo sokuqala, kwaye ngokukhula komphetho owenziwe ngusihlalo, umgca ubuyiselwa kwi-periodic structure ye-5756 rings, i.e. xa ulwakhiwo lweembambo luphindaphinda i-pentagon yokulandelelana - i-heptagon - i-pentagon - i-hexagon.
Ubalo lwethiyori ye-Density functional lubonisa ukuba i-zigzag fin engalungiswanga kunye ne-5756 chair fin zezona zizinzile. Umda we-5756 wenziwa ngenxa yeziphumo ezidibeneyo ezinciphisa inani leebhondi ze-hydrogen ezingaxutywanga kunye nokunciphisa amandla obunzima.
Izazinzulu zikhumbula ukuba iinqwelomoya ezisezantsi zomkhenkce onehexagonal zihlala ziphela kwiimbambo ezizigzag, kwaye iimbambo ezimile okwesitulo azikho ngenxa yoxinaniso oluphezulu lweebhondi zehydrogen ezingaxutywanga. Nangona kunjalo, kwiinkqubo ezincinci okanye apho isithuba sinqongopheleyo, amaphiko esitulo anokunciphisa amandla abo ngokuhlengahlengiswa ngokufanelekileyo.
Njengoko kukhankanyiwe ngaphambili, xa ukukhula komkhenkce kwi-120 K yamiswa, isampuli yapholiswa ngokukhawuleza kwi-5 K ukuzama ukukhenkceza i-metastable okanye i-transition edge izakhiwo kunye nokuqinisekisa ubomi besampulu ede kakhulu kwisifundo esineenkcukacha usebenzisa i-STM kunye ne-AFM. Kwakhona kwakunokwenzeka ukuvuselela inkqubo yokukhula kwe-ice-dimensional-dimensional ice (umfanekiso weNombolo ye-3) ngokubonga kwi-CO-functionalized microscope tip, eyenza kube lula ukufumanisa izakhiwo ze-metastable kunye nenguqu.
Kwimeko yeembambo ze-zigzag, i-pentagons nganye ngamanye amaxesha ifunyenwe ifakwe kwiimbambo ezithe tye. Banomgca ngokulandelelana, benze uluhlu kunye ne periodicity ye 2 x aice (aice yilathisi engaguqukiyo yomkhenkce omacala mabini). Olu qwalaselo lunokubonisa ukuba ukukhula kwemiphetho ye-zigzag kuqalwa ngokuqulunqwa kweqela leepentagoni (periodic array of pentagons).3, inyathelo 1-3), elibandakanya ukongeza iipere ezimbini zamanzi kwi-pentagon (iintolo ezibomvu).
Emva koko, uluhlu lweepentagons ludityanisiwe ukwenza isakhiwo esifana ne-56665 (3, isigaba 4), kwaye emva koko ibuyisela inkangeleko ye-zigzag yokuqala ngokongeza umphunga wamanzi.
Ngemiphetho emise okwesitulo imeko ichaseneyo - akukho luhlu lweepentagons, kodwa endaweni yoko izikhewu ezimfutshane ezinje nge-5656 emphethweni zihlala zibonwa. Ubude be-5656 fin bufutshane kakhulu kunobu be-5756. Oku kunokwenzeka ngenxa yokuba i-5656 fin inoxinzelelo oluphezulu kwaye ingazinzanga kuno-5756. umphunga wamanzi (3b, isigaba 2). Emva koko, amakhonkco angama-656 akhula kwicala elinqamlezileyo, enze umphetho wohlobo lwe-5656 (3b, isigaba 3), kodwa ngobude obulinganiselweyo ngenxa yokuqokelela amandla okuguqula.
Ukuba isibini samanzi songezwa kwi-hexagon ye-5656 fin, i-deformation inokuthi ibe buthathaka ngokuyinxenye, kwaye oku kuya kuphinda kuholele ekwakhiweni kwe-5756 fin (3b, isigaba 4).
Ezi ziphumo zingasentla zibonisa kakhulu, kodwa kwagqitywa ekubeni zixhaswe ngedatha eyongezelelweyo efunyenwe kwizibalo ze-molecular dynamics zomphunga wamanzi kumphezulu we-Au (111).
Kwafunyaniswa ukuba iziqithi zomkhenkce ezinomaleko ophindwe kabini ze-2D zakhiwe ngempumelelo kwaye zingathintelwa kumphezulu, nto leyo ehambelanayo novavanyo lwethu lokuqaphela.
Umfanekiso #4
Kumfanekiso 4 Indlela yokubunjwa okuhlangeneyo kweebhulorho kwiimbambo ze-zigzag iboniswa inyathelo ngesinyathelo.
Ngezantsi zizixhobo zemidiya kwesi sifundo kunye nenkcazo.
Imathiriyeli yemidiya No. 1
Kuyafaneleka ukuba uqaphele ukuba i-pentagon enye eqhotyoshelwe kumda we-zigzag ayikwazi ukwenza njengeziko le-nucleation yendawo ukukhuthaza ukukhula.
Imathiriyeli yemidiya No. 2
Endaweni yoko, uthungelwano lwamaxesha athile kodwa olungaqhagamshelwanga lweepentagon luqala lubumba kumda we-zigzag, kwaye iimolekyuli zamanzi ezingenayo zilandelayo zizama ukudibanisa ezi pentagons, okukhokelela ekwenziweni kohlobo lwekhonkco lohlobo lwe-565. Ngelishwa, eso sakhiwo asikhange sibonwe ngexesha Uqwalaselo olusebenzayo, oluchaza ubomi bayo obufutshane kakhulu.
Izinto zeMedia No. 3 kunye neNombolo ye-4
Ukongezwa kwesibini samanzi sidibanisa uhlobo lwe-565 kunye ne-pentagon esondeleyo, okubangelwa ukubunjwa kohlobo lwe-5666.
Isakhiwo sohlobo lwe-5666 sikhula ecaleni ukwenza uhlobo lwe-56665 kwaye ekugqibeleni luphuhlise kwi-lattice ene-hexagonal edibeneyo.
Izinto zeMedia No. 5 kunye neNombolo ye-6
Kumfanekiso 4b ukukhula kuboniswa kwimeko ye-armchair rib. Ukuguqulwa ukusuka kuhlobo lwama-575 amakhonkco ukuya kuhlobo lwama-656 amakhonkco luqala ukusuka kumaleko asezantsi, ukwenza i-composite ye-575/656 isakhiwo esingenako ukwahlulwa kuhlobo lwe-5756 fin kwiimvavanyo, kuba kuphela umaleko ophezulu womkhenkce onamanqwanqwa amabini anokubonakaliswa. ngexesha lovavanyo.
Imathiriyeli yemidiya No. 7
Ibhulorho ephumela kwi-656 iba liziko lenucleation ekukhuleni kwe-5656 rib.
Imathiriyeli yemidiya No. 8
Ukongeza imolekyuli enye yamanzi kumda we-5656 kukhokelela kwisakhiwo semolekyuli esingahambanga kakhulu.
Imathiriyeli yemidiya No. 9
Ezimbini kwezi molekyuli zamanzi zingasebenziyo zinokudityaniswa emva koko zibe kwisakhiwo esizinzile se-heptagonal, ukugqiba uguqulo ukusuka kwi-5656 ukuya kwi-5756.
Ukuze ufumane ulwazi oluthe kratya malunga nee-nuances zophononongo, ndincoma ukujonga .
Ipilo
Isiphelo esiphambili solu phononongo kukuba ukuziphatha okubonwayo kwezakhiwo ngexesha lokukhula kunokuba yinto eqhelekileyo kuzo zonke iintlobo ze-ice-dimensional ice. Iifom zeqhwa ze-Bilayer ze-hexagonal kwiindawo ezahlukeneyo ze-hydrophobic kunye naphantsi kweemeko zokuvalelwa kwe-hydrophobic, kwaye ngoko ke inokuqwalaselwa njenge-crystal ye-2D ehlukeneyo (i-2D ice I), ukubunjwa kwayo akunamvakalelo kwisakhiwo esingaphantsi kwe-substrate.
Izazinzulu zithi ngokunyanisekileyo ubuchule babo bokucinga abukakulungeli ukusebenza ngomkhenkce omacala-ntathu, kodwa iziphumo zokufunda umkhenkce onamacala amabini zinokusebenza njengesiseko sokucacisa inkqubo yokwakheka kwesalamane sevolumetric. Ngamanye amazwi, ukuqonda ukuba ulwakhiwo olune-dimensional ezimbini lwenziwa njani sisiseko esibalulekileyo sokufunda ezine-dimensional ezintathu. Kungenxa yale njongo ukuba abaphandi baceba ukuphucula indlela yabo yokusebenza kwixesha elizayo.
Enkosi ngokufunda, hlala unomdla kwaye ube neveki emnandi bafana. π
Ezinye iintengiso π
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